Popular Astronomy
Vol. XXXIX, No. 7 AUGUST-SEPTEMBER, 1931
Whole No. 387
SHOOTING LIGHTNING
By JOHN W. BAECHLE.
About ten o’clock one night in May, a terrific thunder-storm swept
down from Lake Erie and over St. Charles Seminary, Carthagena,
Ohio. It was heralded by profuse lightning which flashed beautifully
in the otherwise. inky black northern sky, but the storm was yet so far
away that not a sound of the accompanying thunder could be heard. Be-
catise On several previous occasions I had unsuccessfully attempted to
take a picture of lightning, I most readily grasped this opportunity,
especially since I had never before seen lightning occur at such regular
intervals that I could actually rely upon its continued recurrence. Quick-
ly I secured a companion to help me set up my camera so that I could
obtain the picture before the storm would be upon us in all its fury.
Nature herself seemed very propitious for most of the lightning was
in a very ideal part of the sky, for I was able to include in the panorama
four tall pine trees, which when silhouetted against the lightning-
illumined sky took on the aspect of four stalwart sentries of the night.
Low over the eastern portion of the horizon, which was to be included in
the picture, hung heavy foreboding clouds which could be seen only be-
cause the upper part of the lightning there was abruptly hidden by
them. Such was the scene as I made the accompanying picture of
lightning (Plate VIII).
I had one difficulty, however, for before I could focus the lightning
on the ground glass of my camera, the flash would again be gone; and
I could not focus on anything else, for all was ebony black. Then I
thought of my high-powered flash-light, and so I had my companion
go about 100 feet away and throw the light directly into the lens of my
camera. It was comparatively easy to focus the camera on the steady
rays from the flash-light shining out in the darkness of the night. I
knew that when an ordinary camera is focused on 100 feet, everything
up to infinity is supposed to be in focus, so I figured that the lightning
should also be in focus, for while it was many miles away, it was cer-
tainly included in “Infinity.”
Then without using any supplementary lens on my Conley F 7.7
camera, I gave the film an exposure of probably thirty seconds. I did
not really time the exposure, but merely left the lens open until I
thought that enough lightning had been recorded on the film to produce
a good negative. I knew there was no danger of over-exposing the film
since between the various flashes it was too dark to affect the film at all.
Until I had developed the film I doubted whether the film was able to
366 Astronomy Section of the A.A.A.S.
record the lightning during the fraction of a second which each flash
lasted, but with Eastman Panchromatic (Super-Speed) film and a good
Anastigmat lens set at F 7.7 I found that such a picture of lightning
was possible. In fact the picture shows even more than a naked eye
could possibly perceive, for I’d defy anyone who saw the large flash of
lightning to the left to tell me that with his naked eye he saw how the
two main lines converged and then diverged again, or that he even
knew there was any of the faint root-like forked lightning present as
the picture shows.
St. CHARLES SEMINARY, CARTHAGENA, OHIO.
ASTRONOMY SECTION OF THE A. A. A. S.
(Report of the Pasadena Meeting)
By SETH B. NICHOLSON.
The astronomical section (D) of the A.A.A.S. met with the Astro-
nomical Society of the Pacific in Pasadena during the week of June
15-20. The Huntington Library and Art Gallery, the California Insti-
tute of Technology, and the Mount Wilson Observatory of the Carnegie
Institution of Washington were hosts for the meetings and many oppor-
tunities for scientific fellowship were provided in addition to the regu-
lar sessions for the presentation of papers.
Among the research exhibits was one which illustrated with models
and photographs some of the recent developments in astronomical
equipment and results. A carefully planned exhibit of photographs and
diagrams illustrated and explained the methods used in determining
the distances and distribution of nebulae and showed the results that
have been obtained in such explorations of space. One of the spectro-
helioscopes designed by Dr. Hale for the systematic study of solar activ-
ity was also exhibited.
On Tuesday morning Section D and the Astronomical Society of the
Pacific attended the symposium of the American Physical Society which
dealt with the present status of the problem of nuclear structure. In
the afternoon Dr. Hale’s Solar Laboratory of the Mount Wilson Ob-
servatory was visited and in the evening the new observatory of the
Pasadena Junior College with its 20-inch reflector was open to the astro-
nomical societies.
On Wednesday morning a program of invited papers was presented
in which Dr. Seares and Dr. Hubble of the Mount Wilson Observatory
told of their latest results. Drs. Seares and Hubble presented their
observational results, the first relating to the general absorption in space
and the second to the distribution of extra-galactic nebulae, while Dr.
Tolman told of his theoretical conclusions regarding the entropy of the
universe as a whole. The societies were especially fortunate in having
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Seth B. Nicholson 367
Professor R. H. Fowler of Trinity College, Cambridge, England, who
reviewed and explained the significance of the recent speculations about
the internal structure of stars. Following his talk Dr. Dunham read a
summary of a paper by Professor H. N. Russell of Princeton which
dealt with certain phases of the same subject.
In the afternoon the machine shops of the California Institute of
Technology Astrophysical Laboratory were open and the visitors saw
the machines with which much of the 200-inch telescope and its equip-
ment will be built. The evening was spent on Mount Wilson where
everyone enjoyed the opportunity of observing with the 100-inch
Hooker telescope and the 60-inch reflector. Early the next morning the
solar tower telescopes were inspected and later the regular session for
papers was held in the dome of the 100-inch telescope. The novel ex-
perience of meeting in the dome in view of the big telescope added
much to the enjoyment of this session. The ability of the dome to
maintain a low temperature throughout the day was amply demonstrated
and the sunshine outside was appreciated by everyone at the close of the
session. An outdoor luncheon, picnic style, at the “Monastery” afforded
an opportunity for a good visit before returning to the valley. That
evening several of the visiting astronomers made a pilgrimage to Santa
Ana to see the long pipe line and instrumental equipment used by the
late Dr. Michelson in his last determination of the velocity of light.
On Friday the session for the presentation of papers was held in the
library of the Mount Wilson Observatory in Pasadena and in the after-
noon the laboratories and shops there were open for inspection. A dinner
at the Huntington Hotel with the Mathematical and Physical Societies
and an illustrated lecture by Dr. Hubble in the eevning closed the astro-
nomical program of the meeting.
At the sessions for technical papers a great variety of subjects was
discussed. No attempt will be made here to review or even mention all
the papers, 33 in number, that were presented. Practically all phases of
astronomy were covered and the societies were given a comprehensive
account of recent progress, especially at the four large observatories of
the west.
The meetings were unusually well attended, with representatives from
the Lick Observatory, Goodsell Observatory, Lowell Observatory, the
Students’ Observatory at Berkeley, the Adler Planetarium in Chicago,
Perkins Observatory, Stewart Observatory, and the Dominion Astro-
physical Observatory in addition to those from the colleges and observa-
tories of Southern California. The opportunities for visiting and for
informal discussions not listed on the printed program were, therefore,
numerous and added greatly to the success of the meetings.
CARNEGIE INSTITUTION OF WASHINGTON,
Mount Witson OsservatTory, Jury 10, 1931.
368 Globular Clusters and the Galaxy
GLOBULAR CLUSTERS AND THE GALAXY*
By EDWARD HARRISON, M.A., F.R.A.S.
The conception that the Galaxy is a spiral nebula seems to be accepted.
It must, however, be a very old spiral which in the course of its wander-
ings through space has collected innumerable other systems and so
formed the immense structure it presents. Shapley well sums up the
matter when he says, “Numerous conditions suggest that the Galaxy is
a heterogeneous assemblage of unequally organised parts. . . . the
galactic system may be largely composed of disintegrating clusters.” In
another paper he puts it more pithily, saying, “the Galaxy is a growing
composite of disintegrating minor systems.”*
It is noteworthy that the different classes of the heavenly bodies have
varied and distinctive velocities. Curtis states these to be :?
For the stars 10 to 30 km/sec
For globular clusters 300 km/sec
For spiral nebulae 1200 km/sec.
Others’ put the mean speed of the globular clusters at 150 km/sec.
If, then, the Galaxy is a spiral nebula it must be travelling through
space at an enormous speed, and it is difficult to imagine any other form
of motion for it than that of a quoit or discus, and this view is adopted
by the majority of astronomers.
It is important that we should know, if possible, the velocity and di-
rection of motion of the Galaxy. From observations on spiral nebulae
estimates have been made by Young and Harper,* Truman, Wirtz, and
Lundmark,® and the average of the estimates of velocities is —692
km/sec, while the directions vary in galactic longitude from 354° to 35°,
and the galactic latitude averages about —30°. The mean direction,
then, is -++-15° galactic longitude, but for the present we will take a
broad view and consider the direction to lie somewhere in the segment
0°-30°, and assume that the speed of the galaxy is three times that of
the average globular cluster.
We will now consider a few of the salient features of the globular
clusters.
Compared with the stellar distribution in the neighborhood of the sun
the concentration of stars in the globular clusters is astonishing. A study
of Messier 3 discloses that in equal spheres there would be only four or
five stars around the sun compared with 15,000 in Messier 3. They are
the nearest of the extra-galactic bodies, and only about a hundred are
known. With very few exceptions they are all approaching the galaxy
which exercises a powerful pull on them, and accelerates their velocity.
Thus of ten studied by Slipher,® the five more remote have a mean
*Adapted from a paper read before the Hull Astronomical Society, England,
April, 1929.
Edward Harrison 369
velocity of 133 km/sec, while the five nearer ones average 155 km/sec.
A suggestion regarding their origin has recently been put forward by
Sir J. H. Jeans. When he announced his theory of the development of
spirals in 1923, he regarded the condensations in the spiral arms as em-
bryo stars. More recent investigation, however, has shown him that
these, at any rate those which are first formed, are far too massive to be
single stars; that indeed they contain sufficient material to form thous-
ands of stars." Further than that, dynamical theory has indicated that
they would be thrown off the revolving nebulae by centrifugal force,
and so might very well account for the production of globular clusters.
This startling theoretical conclusion receives observational support by
the study of such nebulae as M 51 and M 101, both of which are figured
in most of the modern books on astronomy, and in these one can almost
see the little masses being shed. Lundmark® and also Perrine note a re-
lationship between these two classes of celestial bodies. Acceptance of
this hypothesis implies the presence of innumerable globular clusters in
space mOving in every conceivable direction. How is it, then, that only
about a hundred are known? The explanation probably is that as they
are only small objects compared with the parent nebulae, they defy de-
tection until they are comparatively very close to us.
We can now form a mental moving picture of what is in all probabil-
ity happening. The Galaxy is travelling like a quoit and gathering up
all the structures it encounters. As its speed is of the order of three
times that of the globular clusters, it follows that it must be either meet-
ing or overtaking them, with the possible exception of one or two
clusters, here and there, with abnormally high velocities. We should
expect, then, to find that all the globular clusters were on the advancing
moiety of the Galaxy; and, further, as the movement is quoit-like, there
should be an equal number on the upper and lower faces. Hinks® was
the first to point out that the globular clusters were all found on one-
half of the Galaxy, and, later, Shapley’s investigations confined them
nearly all to one-quarter,’® viz., galactic longitude 0°-270°, and showed
that there are none at all in the opposite quadrant. Further, the 69
globular clusters with which he worked were very equally divided be-
tween positive and negative galactic latitudes, and that there was a band
of avoidance exactly in the galactic plane presumably due to the pres-
ence of obscuring matter.”
Now Shapley estimates that, within 125 million years, more than half
of the known globular clusters will have entered the Galaxy, that is one
is absorbed every two or three million years. Astronomically speaking,
125 million years is a mere moment, and if the inclusion of so many
clusters within the Milky Way is imminent, it is only reasonable to
suppose that many have been absorbed in the past.
If this be the case, what has happened to them? There are no globu-
lar clusters in the Milky Way, but, on the other hand, there are many
clusters which are not “globular,” but are of a more diffused, open
character, which naturally leads one to ask whether the globular clusters
370 Globular Clusters and the Galaxy
after their inclusion are converted into open clusters? A priori it would
seem that this was very likely. Imagine a dense globular cluster im-
mersed in the immensity of the Milky Way, encompassed by countless
stars, each of which is exerting a gravitational pull on it. Should we
not expect that it would be teased out into a more open form? Well,
what do we find? According to Shapley,’? “the open clusters occur
only in low galactic latitude, and they do not show the avoidance of the
Milky Way exhibited by the globular clusters. In fact they occur in the
dense stellar regions where globular clusters are not found, and they do
not occur in the extra-galactic realms where globular clusters are. This
apparently complementary distribution of the two types of clusters is
of high importance for the hypothesis which derives the galactic system
originally from stellar clusters and obtains the open groups of the Milky
Way from the extra-galactic globular organizations.” A special survey
was made with the result that “the evidence grows continually stronger
that open and globular clusters occupy regions of space that are mutual-
ly exclusive.” We have, then, a quickly moving Galaxy, travelling
through space which is dotted all over with globular clusters which are
moving in all directions at, on the average, about a third the pace of the
Galaxy.
Slipher found that the velocities of ten globular clusters, which he ex-
amined, varied from +225 to —410 km/sec which is a range of 635
km/sec, which may be regarded, provisionally, as consisting of 150 due
to the clusters and 480 for the Galaxy. Slipher’s figures, however, show
that although 150 km/sec may be taken as the average rate there is a
considerable range in their velocities. Thus, one (N.G.C. 6333) is re-
ceding at the rate of 225km/sec. This is no doubt exceptional, but it
makes one ask, are there any globular clusters overtaking us?
Shapley’s diagram shows three in the segment 180°-210°.
Apart from these exceptions Slipher’s list has one at +10, one at
—10 and one at +10, which means that we must admit that some are
moving at very much the same velocity as ourselves, so that although we
may be right in assuming the average cluster velocity to be 150 km/sec,
and to have a ratio of about 1 to 3 compared with the galactic velocity,
yet it may range from 0 to 6. It must be remembered that these observed
velocities are all radial, so that it is the radial component of globular
clusters travelling obliquely to our direction that is observed. This ex-
plains the large percentage of clusters having apparently such low in-
trinsic speeds.
Figuring these movements to ourselves, let us endeavor to predict, as
far as possible, the distribution of the galactic clusters.
It is clear that we may divide the galactic clusters into two classes
which we will for convenience designate as the “overtaken” and the
“met,” the latter probably being about twice as numerous as the former
(vide appendix).
Now, the mode of admission of the two classes into the Galaxy will be
very different. Those overtaken will enter in a passive manner, their
i i a
Edward Harrison 371
speed of ingress varying inversely with their intrinsic velocity. Thus,
those travelling directly away from us at almost our own pace will be
caught only after a long stern chase, and when overtaken will be lightly
licked up and engulfed by the Galaxy. Once inside, they will not tend to
travel far inwards, as what little velocity they had on admission will be
rapidly reduced to that of the Galaxy, and they will quickly disintegrate
and cease to exist as “clusters.” Let us call these sub-class A. Those
having a lower intrinsic radial velocity will be overtaken more easily,
that is after a shorter stern chase, and so will enter with a greater velo-
city and consequently advance deeper into the Galaxy before their speed
is reduced, and will therefore remain as “clusters” longer than those of
sub-class A. We will name these sub-class B.
boslercor
Figure 1.
Bearing in mind that the globular clusters are moving in every possi-
ble direction, it is clear that they will enter the Galaxy at all angles. Sup-
posing, then, that we could look down on the Galaxy we should expect to
find that the advancing portion of the Galaxy would contain the ‘‘over-
taken” clusters, and that these would be divided into two zones, an
anterior and a posterior, which would blend gradually with each other,
but the posterior would contain more clusters. Further, we should ex-
pect to find that the clusters in the anterior zone, (sub-class A), were of
a more open character, i.e. commencing disintegration being visible.
a
“Teskrnor
Figure 2.
On the other hand the “met” clusters will enter in a distinctly more
agressive manner. As they come with an intrinsic velocity which must
be added to, instead of subtracted from, the galactic velocity, they will
go deeper and will not disintegrate so quickly, and, as we have seen
that there will be about twice as many in this class, there should be more
clusters found in the posterior half of the Galaxy. Furthermore, as
372 Globular Clusters and the Galaxy
there is a very decided difference in the average velocity of entrance of
the “met” and “overtaken,” we should expect to find a decided line of
demarcation between these two, though not of course absolutely abrupt,
and, moreover, this division should be at right angles to the direction of
galactic movement. It will not be absolutely abrupt as those globular
clusters travelling at right angles to the course of the Galaxy will have
no intrinsic radial velocity and would so bridge the gap between “met”
and “overtaken.”
:
BD = *,4 <<. yO
— 330
OS
4o 29
Ficure 3.
Figure 1 shows the anticipated distribution supposing that we could
look down on the Galaxy, but it only indicates the dispersion in galactic
longitude. As the clusters come in at all angles there will be some dis-
persion in galactic latitude, and the degree of this dispersion will depend
Edward Harrison 373
on the distance travelled within the Galaxy, hence we should expect to
find the spreading greater in the posterior portion. A glance at Figure
2 will make this clear.
Now, the actual distribution of clusters within the galaxy is closely
in accord with our expectations. Figure 3, which is made from
Melotte’s'* catalogue of star clusters shown on the Franklin-Adams
chart plates, shows the positions in galactic longitude and galactic lati-
tude for all the clusters. Galactic longitude is marked in degrees on the
circumference, while the galactic latitude is indicated by a + or —
marking the position of each cluster.
We are assuming the Galaxy to be moving in a direction between 0°
and 30°. A mere glance at the diagram shows that there are many more
clusters in the posterior portion, and that they are more widely dispersed
in galactic latitude, the maximum range being found between 150° and
210°. Moreover, the anticipated line of demarcation between the two
classes of clusters is very obvious, stretching from 90° to 310°, at right
angles to the line from 20° to 200°. This is in accord with the assumed
direction of galactic movement.
c ° '
'
'
Fs)
16
10
Figure 4.
The distribution in galactic longitude is more clearly shown in Figure
4, made from Melotte’s catalogue, the upper thick line marking the total
number of clusters found in each segment of 30°. The first thing that
strikes one on looking at this curve is the very marked maximum in
segment 180°-210°, which is the one exactly opposite the advancing seg-
Figure 5.
The circle represents the Galaxy. A globular cluster situated at A and having
an intrinsic motion in the direction AB will pass through the center of the Galaxy.
This is what we will term a “direct hit.” A cluster moving in the direction AC
will be deflected as it approaches the Galaxy and will take the course AD.
374 Globular Clusters and the Galaxy
ment 0°-30°. This might have been anticipated, and its existence sup-
ports the assumption that the direction of galactic movement is between
0° and 30°. In Figure 5, let the circle represent the plane of the Galaxy,
and suppose a globular cluster at A is moving directly towards the
center of the Galaxy, which is itself moving in a diametrically opposite
direction, viz., both along the line BEA. The globular cluster will, pass-
ing through the center, reach the point B. Let us call such an encounter
a “direct hit.”
Now, the gravitational attraction exercised by the galaxy on the glob-
ular clusters will be directed towards its center. Imagine a globular
cluster at A pursuing a course AC, so that if gravitational attraction
were absent it would reach the point C; but the galactic attraction de-
flects it from this straight course and impels it to arrive at D, and so
makes it approximate to the line taken by a “direct hit.” We ought,
therefore, to have expected to find more clusters in segment 180°-210° ;
and further than that, the increase should have been at the expense of
the adjacent segments, which ought then to contain fewer clusters than
the normal. These considerations would, perhaps, have justified a fore-
cast and this forecast, had it been made, would have been verified in an
almost uncanny degree, for an increase of 11 in segment 180°-210° is ac-
counted for by a loss of 4 (i.e. 17 —13) in segment 150°-180° on the
one side, and of 4 (1.c. 16 — 12) in segment 210°-240°, and 3 (i.e. 16 —
13) in segment 240°-270°, on the other side, as reference to Figure 4
will show. The dotted line shows the curve thus smoothed out, and it
then becomes practically a straight line extending through eight seg-
ments, viz., 90°-120° to 300°-330° inclusive.
This remarkable finding almost forces one to inquire further and
examine the details of the distribution within segment 180°-210°, in or-
der to see if we can lessen the limits of the adopted direction of galactic
movement. Dividing the segment into three, of 10 degrees each,
Melotte’s tables show that the total number of 27 is made up of 14 in
the central sub-division, and of 5 and 8 on either side, which would seem
to indicate that the direction is between 10° and 20° galactic longitude.
The mean of the observations already mentioned, viz. 15°, is within this,
as is also one of Lundmark’s, viz. 17°. Thus, incidentally, we have
two quite independent and concordant pieces of internal evidence indi-
cating that the Galaxy is pursuing a course along the line drawn from
200° to 20° galactic longitude. It is as if the Galaxy had produced two
records of its own path through space, like the tracks left by two cart
wheels, or the trail of foam in the wake of a steamer.
The other important feature of the curve is the sudden and marked
fall in segments 330°-0° to 60°-90°, which of course corresponds with
the line already noticed stretching across from 90° to 310°, (indicated
by vertical dotted lines in the diagram), which was considered as that
separating the “met” from the “overtaken” clusters.
We will now consider the distribution in this advancing portion of the
Galaxy, taking first:
Edward Harrison 375
Sub-Class A. These are what we have pictured as lightly gathered
up and engulfed after a prolonged stern chase, and at first one would
think that they would be very few in number. Examination, however,
of Slipher’s table (vide appendix) shows that out of his ten clusters two
(N.G.C. 6626 and 7089) might well be placed in sub-class A; that is to
say twenty per cent. We have seen that Shapley prognosticates that
more than half of the globular clusters (say 50) will enter the Galaxy
in 125 million years, so assuming that this rate has been the same in the
past we should have taken up ten sub-class A clusters during the past
125 million years. These, we have anticipated, would not have remained
as clusters but would have rapidly disintegrated into clouds of stars.
Well, those wonderful star clouds in Sagittarius, in Scorpio, in Ophiu-
chus, in Scutum and up to Cepheus, are in the advancing portion ex-
tending from 60° to 320° galactic longitude.
These stellar clouds have been accounted for by assuming that the sun
is situated eccentrically on the opposite side of the Galaxy (galactic
longitude 145°) so more stars are seen here as we are looking through
a greater depth of Galaxy. But, on the assumption that the stars are
fairly evenly distributed, seeing through a greater depth should still
show an even, though denser, distribution. Now, Barnard’s beautiful
plates of the Milky Way give anything but an impression of homogen-
eity. The stellar increase suggests that they are additions forming
colossal clouds, many having well marked margins, and giving no indi-
cation of uniformity. Further than this, their appearance suggests dis-
integration, and this has been pointed out by Barnard himself, as he
says in his description of plate 42 of a region in Sagitta (galactic longi-
tude 22°) “All along the edge of the cloud—and this is noticeable in
other parts of the Milky Way—the impression is strong that the stars
are moving out, as if disintegration were in progress.”
Another interesting feature of these star clouds is that they seem to
indicate that the Galaxy is rotating in the direction 360°-330°-300°, as
the more definite margins are all on the sides having the smaller galactic
longitude which is what one would have anticipated on the assumption
that this was the direction of rotation. This rotation explains the distri-
bution of the clouds extending as far as 320° (i.e. 40° from 0°), those
now seen at 320° being probably the oldest, having been carried round
from segment 0°-30°, and this supposition is supported by Barnard’s
photographs, particularly by Plate 51 in which the gradual dissipation
of the advancing margin is well brought out. Here it is seen that the
well-defined margin in galactic longitude 14° is retained as far as galac-
tic longitude 354°, after which it gradually loses its clearness till it be-
comes lost at 324°.
We have already anticipated that the sub-class A zone would be char-
acterized by the presence of clusters of a more open variety. We have
seen grounds for assuming that the rapidity of disintegration of a clus-
ter will vary inversely with its initial speed. We should, then, expect to
find the clusters had varying degrees of concentration in all parts of the
376 Globular Clusters and the Galaxy
Galaxy, but as sub-class A zone contains the most slowly moving
clusters more of these should be opened out. Is this the case?
Fortunately Melotte has divided the galactic clusters in his catalogue
into three classes, viz.,
1. Loose clusters having regular, well-defined outlines.
2. Loose clusters, often of a few stars only, and of irregular outline.
3. Coarse clusters, only 14 in number, e.g. Pleiades.
We thus have data for an answer to our query, and for our present
purpose we will take the second and third groups together and call them
“open” clusters, while the first class we will designate as “close” clusters.
In Figure 4 these two classes are plotted, the “close” class as a thin
continuous line, and the “open” as a broken line; the sum of the two
giving, of course, the upper heavy line we have been considering. We
find a very definite pronouncement in favor of our expectation. In
every part of the curve, with the exception of the advancing segments,
the thin line is well above the broken one. This is, however, reversed
in the two central segments of the advancing portion, while in segment
0°-30°, which we have taken to be the leading segment, all the clusters
are of the “open” variety. Another factor in the causation of the fall
in the curve, and which makes it deeper, is the absence of those clusters
which have already disintegrated into star-clouds. The actual number
of clusters found between 90° and 310° is 40. If we take Slipher’s pro-
portion of 1/5 as those disintegrated, there would have been 50 origin-
ally absorbed, ten of which have ceased to exist as clusters.
The question then arises, would so few clusters account for the ex-
isting dense stellar clouds? A discussion of this point would carry us
beyond the scope of this paper, but it may be pointed out that, as already
noted, the density of stars in the globular clusters is very great, and
Jeans has said that the stellar density in a globular cluster “must be
very great indeed in comparison with that in the galactic system.” Then
a globular cluster would not disperse into a spherical form, but would
rather tend to assume the shape of a meniscus, as the attraction towards
the galactic center will be far greater than that of the periphery.
Another point of interest is that, taking 50 as the number of “over-
taken” clusters, there would then have been 173 in all, so that the “met”
would number 123, just two and a half times as many, and this means
that the Galaxy is travelling two and a half times as fast as the average
globular cluster, which is well in accord with the adopted number (vide
appendix).
Observational findings, then, are in very close accord with theoretical
anticipations, thus:
1. The visible globular clusters are all on the advancing half of the
Galaxy, their apparent maximum at galactic longitude 325° being due
to the eccentric position of the sun.
2. The line suggesting demarcation between “overtaken” and “met”
clusters is at right angles to the assumed direction of motion, and is
clearly defined.
Edward Harrison 377
3. The ratio between the numbers of “met” and “overtaken’’ clusters
would seem to indicate that the Galaxy is moving at the rate of two and
a half times that of the clusters.
4. The distribution of galactic clusters is that anticipated theoretical-
ly, and has provided two independent and concordant pieces of internal
evidence as to the direction of galactic movement, which is very nearly
the mean of the estimations of several observers.
5. The presence and position of the stellar clouds accord with theory.
6. The ratio between the number of “open” and “close” galactic clus-
ters, in different zones of the Galaxy, agrees with theoretical expecta-
tions.
APPENDIX.
Table to show the relationship between the speed of the Galaxy to the
numbers of “met” and “overtaken” galactic clusters.
Ratio of Speed of Galaxy to Ratio of “Met” to “Overtaken”
Speed of Clusters Globular Clusters
BP Aiea ieee oak ok Reed eee ee eee 3
3 ae
rR ee ea ie ee ee eure eee 1.68
Be piste oe eke bakes Se od eke eas oo
SLIPHER’S RADIAL VELOCITIES OF TEN GLOBULAR CLUSTERS.
N.G.C. mA. Dec. Vel. Gal. Lon. Gal. Lat.
7 : km/sec sf .
5024 197.0 +18.7 —170 320 +78
5272 204.4 +28.9 125 15 +80
5904 228.4 + 2.5 +. 10 333 +45
6205 249.5 +36.7 — 300 18 +38
6333 258.3 —18.4 +225 333 + 7
6341 258.5 +43.3 —160 32 +32
6626 274.6 —24.9 + © 337 0
6934 307.3 + 7.1 —410 22 —24
7078 321.3 +11.7 - 95 31 —29
7089 aee.1 — 1.3 — 10 21 —34
The average direction in galactic longitude is 350°, not so far from the aver-
age we have taken from estimates made from spirals.
REFERENCES.
1. SHApPLEY. Astrophysical Journal, Sept., 1919, p. 108; “The Galactic System.”
Address to the British Astronomical Society, May 31, 1922. Nature, Oct.
21 and 28, 1922. Popular Astronomy, May, 1923.
. Curtis. Scientia, Vol. XXXV, No. CXLI-I, 1-1-1924, p. 4.
. Jeans. “Astronomy and Cosmogony,” p. 25.
. Younc AND Harper. “The Solar motion as determined from the radial velo-
cities of Spiral Nebulae.” Journ. R.A.S. Canada, 1916, p. 134.
5. LunpMArK. “Relations of the Globular Clusters and Spiral Nebulae to the
Stellar System.” Kungl Svenska Vetenskapsakademienshandlingar. Band
60 No. 8. London. Wesley and Son.
. SHApLEY. Pub. Ast. Soc. Pac., Feb., 1918.
. Jeans. “Astronomy and Cosmogony,” p. 371.
. LunpMARK. ibid. No. 9, p. 34.
. Hinxs. “Nineteenth Century,” May, 1927, and M.N.R.A.S., LXXI, (1911),
p. 176.
t GW do
WON
378 Globular Clusters and the Galaxy
10. SHApLEY. Numerous papers in Astrophysical Journal, and Pub. Ast. Soc.
Pac., Feb., 1918.
11. Fatu. “Elements of Astronomy,” p. 252-3, and SeAres. Nature, May 5, 1928.
12. SHAPLEY. Astrophysical Journal, Sept., 1919, p. 108.
13. Memoirs R.A.S., Vol. LX, Part V.
ADDENDUM,
Since writing the above, Shapley’s Monograph on “Star Clusters,”
containing a catalogue of 249 galactic clusters, has appeared; also
Trumpler’s paper (Lick Observatory Bulletin, 420) with 334 open clus-
ters. Publication of this paper has, therefore, been delayed pending ex-
amination of these two recent communications.
Working with Shapley’s list the minimum is confined to the segments
0°-30° and 30°-60° (each containing 10 clusters) rising rapidly on
either side to 21 and 22. It is, thus, more nearly symmetrical than
Melotte’s, and so more in accord with theoretical anticipations. Shap-
ley’s gravitational maximum at 180°-210° is somewhat abortive. This
is partly due to the omission of two of Melotte’s clusters, and when al-
lowance is made for this the resemblance is restored.
$a
“4
lye
344
Ficure 6.
A marked divergence from Melotte’s curve, however, is at 300°-330°
where there is a maximum of 36, and a lesser one of 30 at 240°-270°.
Figure XII, 4, in Shapley’s book shows the galactic clusters projected
on to the galactic plane, so that galactic longitudes are indicated, and
also the distance of each cluster from the sun. Inspection of this dia-
gram discloses that the maximum in these two segments is due to
agglomerations of clusters at the apices of the two segments, that is
very near the sun. When we remember that the direction of the maxi-
379
Earthshine
mum of the globular clusters, 327°, falls within segment 300°-330°, we
are provided with a clue, viz. the eccentric position of the sun, and by
moving the centre a few hundred parsecs along 327°, these maxima dis-
appear and the curve approaches very closely to that of Melotte’s, of
course on a higher level.
Trumpler, who gives a similar diagram of 334 clusters and, after
recording the results of several observers, concludes that the galactic
centre lies 350 parsecs distant from the sun in galactic longitude 325°
Taking this as the centre, counts of the clusters in each segment result
in the curve in Figure 6, Melotte’s curve, the broken line, being placed
below it for comparison.
We see, as was the case with Shapley’s, that the minimum is more
marked than Melotte’s, and is confined to two segments.
It is all on a grander scale; the opposing maximum extends over two
segments, the gravitational minima on either side being very pro-
nounced. A very noticeable symmetry exists about the maximum, 150°-
210°, extending on either side to 60°-90°, and 270°-300° respectively,
this covers eight segments. Then in 300°-330° and 330°-0°, we have
what may be considered a normal distribution, followed by the minimum
extending over two segments.
These two segments of “normal” distribution somewhat mar the sym-
metry of the whole diagram, and incline one to ask whether galactic
rotation would account for it.
Respecting the distribution in galactic latitude, both Shapley and
Trumpler emphasize the increase in the spread in the posterior portion.
9 ParK AVENUE, HULL, ENGLAND.
EARTHSHINE
A Crayon Sketch
Evening—
And the black edge of night already laps
Westward where the stark outline of trees is set
In the softening glow of day
Now almost gone.
New moon—
And its silver rim of light low hung in graying sky
Halos a softer radiance as though
The darkness of the lunar night was lightly brushed
With dust of stars.
And now—
Against the background of the waning twilight
And an earthlit moon
A tiny bat flaps dusky wings—,
And day is done.
STERLING BUNCH.
Knoxville, Tennessee.
380 Accuracy Required in Parabolizing a Mirror
ACCURACY REQUIRED IN PARABOLIZING A MIRROR
By FRANKLIN B. WRIGHT.
Many amateurs are making their own reflecting telescopes, and the
number is increasing steadily. The practical methods used in grinding,
figuring and testing the objective are clearly described in the book
“Amateur Telescope Making,” published by the Scientific American
Publishing Company. In his own efforts along these lines the writer
has felt the need for more definite information concerning the accuracy
required in shaping or figuring the objective mirror. The question is
discussed here and there in the literature but not in a manner immedi-
ately and simply applicable to the amateur’s own reflector. A number
of inaccurate statements are also to be found. For example, the article
on diffraction of light in the Encyclopaedia Britannica (11th ed. Vol. 8,
p. 245) concludes by an indirect method of reasoning frequently em-
ployed that a spherical mirror of 3 feet focus can not exceed 2.5 inches
in aperture without introducing a surface error greater than A ~ 8,
while the formula for e discussed below shows directly that an aperture
of 3.5 inches is permissible for the focus and surface error there as-
sumed,
In figuring the objective mirror accurately to the parabolic shape re-
quired to bring the rays of light to a perfect focus, the mirror maker
uses the Foucault knife-edge test as his guide. This simple but beautiful
test is usually applied by amateurs at the center of curvature of the
mirror in the following manner, since this requires less apparatus than
when tested at the principal focus. The mirror is set on a stand with its
axis about horizontal. A lamp having a metal shade with a very small
hole punched in it serves as a point source of light. This remains in a
fixed position throughout the test near the center of curvature slightly
to one side of the axis. The light reflected from the mirror then comes
to a focus near the lamp on the other side of the axis. A razor blade
or similar straight edge, fastened on a stand, is used to locate this point
accurately in a manner fully described in the reference given above.
When the mirror is spherical the rays from all zones of the mirror focus
precisely at this point. But when the mirror is parabolic, the rays from
any narrow zone a distance r from the center come to a focus farther
away from the mirror than the rays from the central zone of the mirror
by an amount approximately given as d—=r* +R, R being the radius
of curvature.
In parabolizing a large mirror measurements are made for a number
of zones, but with mirrors of, say eight inches or less, only the outermost
zone need be compared with the center, provided the general shape of
the mirror appears all right when viewed as a whole with the knife
edge. Considerable difficulty is experienced in figuring a mirror so that
the measured distance d checks precisely with that given by the formula.
Franklin B. Wright 381
It is therefore worth while to inquire just what error may be tolerated
without materially damaging the definition of the finished telescope.
In order to answer this question, consider the spherical and parabolic
surfaces shown in Figure 1. The paraboloid A is supposed to be drawn
with the same radius of curvature R for the center zone O as the spheri-
cal surface B. The distance between the two surfaces at a distance r
from the center is given to a close approximation by e == r* + 8R°, or
more conveniently by e = D ~ 1024f* where D=2r and f= R ~— 4r.
This expression may be derived easily from the equations of the two
surfaces* after first expanding a radical appearing in the spherical equa-
tion by the binomial theorem. It has been checked with calculations for
several mirrors by Ritchey and Young.
Table I gives the values of e at the edge of mirrors of small aperture
D and various ratios f of equivalent focal length to aperture. They have
been expressed in terms of the wavelength of light by dividing e by
A= 0.00002 inch, approximately representing visible light.
TABLE I.
MAXIMUM DEPARTURE € OF SPHERICAL FROM PARABOLIC SURFACE.
f Ratio D=4inches 6inches 8inches 10 inches 12 inches
r r nN r
5 1.56 2.34 3.82 3.90 4.69
6 0.90 1.36 1.81 2.26 2.72
8 0.38 0.57 0.76 0.95 1.14
10 0.20 0.29 0.39 0.49 0.59
12 0.11 0.17 0.23 0.28 0.34
The process of parabolizing may conveniently be supposed to consist
of polishing off a depth of glass equal to e near the edge of the spherical
surface, although in practice it is usually the surface around the center
rather than the edge of the mirror that is thus treated to obtain a
parabolic shape. If the mirror receives only a partial correction, say 80
per cent of the theoretical amount e, then 20 per cent of e is the error of
the resulting surface giving it the shape shown by C in Figure 1. For
this surface the knife edge test in the form which has been outlined
gives a measured distance of 80 per cent of r° + R between the knife
edge positions for the central zone and any other zone of radius r.
Authorities generally agree that an error of surface of an eighth of
a wavelength scarcely affects definition at all, and even twice this
amount, or A + 4, has very little effect when the telescope is adjusted
for best focus. Above this limit an appreciable scattering of light com-
mences to take place. On first thought this seems to be a surprisingly
large tolerance since the difference in the paths of the light rays from
the center and edge of the mirror is twice the error of the surface, anda
difference in path of A + 2 would surely be expected to produce a lot of
destructive interference at the focus. However, the best focus for the
surface does not correspond to the paraboloid of Figure 1, but rather
*R, K. Young: Jour. Royal Ast. Soc. of Canada, Jan. 1930, p. 17.
382 Accuracy Required in Parabolizing a Mirror
to another paraboloid (not shown) intersecting the mirror surface both
at its edge and at its center. The error of surface which is here referred
to is the nominal error useful for purposes of calculation, the actual
maximum error being only about one-fourth as great when the telescope
is properly focused for best definition, Contrary to what one might
suppose, errors of surface even considerably in excess of these specified,
do not enlarge the image of a star. The effect is rather to cause a cer-
tain amount of scattered light around the image and brightening the
surrounding diffraction rings. With an error of A +4 about 1.5 per
cent of the light which should be concentrated at the focus is thus
scattered.
This explanation has been made rather at length because diffraction
theory is apt to be rather too involved in mathematical symbols for most
of us who have not delved into the subject much further than a general
course in physics. The subject has been discussed mathematically by
Buxton in Monthly Notices of the Royal Astronomical Society, 81,
page 547. Bell’s book, “The Telescope” (page 265, etc.) contains a
discussion of the subject in non-mathematical language.
In view of these facts it may be safely assumed that if e is reduced
to A + 4, the objective will perform well in service. It is better to under-
parabolize a mirror somewhat, unless it is made of pyrex or quartz in-
stead of ordinary glass. Most amateur telescopes are used more often
Franklin B. Wright 383
during the early evening hours when the temperature is falling than at
other times. Falling temperature temporarily flattens the outer zones
of a mirror tending to parabolize an under-corrected figure. The prac-
tical thing to do is to finish the mirror with an error of surface at the
outside edge of between 0 and A + 4, preferably about half way be-
tween atA +8. Then good definition will be assured even when the
temperature is not falling. Table II has been prepared on this basis for
small Newtonian telescopes with ordinary glass mirrors to be used
chiefly during the evening hours. The first three columns show the
acceptable range of correction expressed in per cent of the knife edge
distance dr? ~ R, and corresponding respectively to A+ 4, A + 8,
and zero errors of surface at the edge of the finished mirrors. The
remaining columns show the ratio of equivalent focal length to aperture
for mirrors of various diameters to which the corrections of the first
three columns are applicable.
TABLE II.
%. of Theoretical Correction
Minimum Maximum
Accept- Preferred Accept- f Ratio
able Correction able D = 4in. 6in. 8in. 10in. 12in.
—100 0 100 11.6 13.3 14.6 15.8 16.8
— 2 40 100 9.8 11.2 12.3 13.3 14.1
20 60 100 8.5 9.8 10.8 11.6 12.3
60 80 100 6.8 7% 8.5 9.2 9.8
80 90 100 5.4 6.2 6.8 7.3 7.8
90 95 100 4.3 4.9 5.4 5.8 6.2
95 97.5 100 3.4 3.9 4.3 4.6 4.9
To illustrate the manner in which computations of this sort may be
made, consider a 10-inch mirror with an equivalent focal length of 60
inches. The f ratio (focal length to aperture) is 6. From Table I this
has an error of surface at the edge of the mirror of 2.26\. The pre-
ferred correction is such as to reduce this error to 0.125. This is
(2.26 —0.125) -~ 2.26 or 94 per cent of the amount necessary to com-
pletely parabolize the mirror. Similarly reduction of the error to 0.25A
gives 88 per cent for the minimum acceptable correction. Table II gives
the resulting percentage corrections with sufficient accuracy, so the mir-
ror maker can read them (by interpolation when necessary) for prac-
tically any mirror up to an aperture of 12 inches.
Suppose a zone % inch in width at the edge of this 10-inch mirror be
compared with the central zone by means of the knife edge test. The
outer zone is at an average distance of r= 4.75 inches from the center,
and the radius of curvature is R= 60 * 2120 inches. The theoreti-
cal distance between the two knife edge positions is therefore r? + R-
0.188 inch. This is the maximum acceptable correction. The preferred
correction is 94 per cent of this or 0.177 inch, and the minimum accept-
able correction 88 per cent or 0.165 inch. In contrast to this case con-
sider a 10-inch mirror with a focal length of 90 inches. The distance
between the two knife edge positions would be 0.079 inch and 0.125
384 Accuracy Required in Parabolizing a Mirror
inch for the minimum and maximum acceptable corrections respectively.
This is twice as wide a range as in case of the shorter focus instrument
and the correction is therefore considerably easier to measure within
tolerable limits of accuracy.
Negative corrections in Table II indicate that the radius of curvature
of the outer zone may even be left somewhat shorter than that of the
central zone without harm. Mirrors of dimensions shown on the first
line of Table IL should preferably be finished spherical. Even those on
the second line may be similarly treated although about 40 per cent cor-
rection would be somewhat better in these cases, particularly with the
smaller aperture mirrors where temperature distortion is not likely to
be as great as with the larger ones. Perhaps it would be well to empha-
size the fact that these spherical mirrors are no makeshift affairs. A
perfectly spherical 8-inch mirror with a focal length of 8 feet will usual-
ly give better definition than one of 4 feet focal length that has been
given an 80 per cent correction. In the writer’s opinion, it is failure
to perform the above calculations that is responsible for the general con-
dition found by Ellison, who says (Amateur Telescope Making, 2nd
Ed., p. 98), “We have never yet seen a mirror of f 10 and upward,
even by well-known makers, that was not over-corrected.” There is
so little difference between a sphere and a paraboloid of long focus that
correction is easily overdone.
It is amazing that more reflectors of small aperture are not made
spherical with aperture ratios of from f 10 to f 13. Not only are they
much easier for the amateur to make and test than those of shorter
focus, but the aberrations for points off the axis are less, they give better
results generally with ordinary 2 lens eyepieces, and are less critical of
exact adjustment of the eyepiece to position of best focus. Perhaps it
is due to the tendency to copy the relative dimensions of the larger pro-
fessional instruments without inquiring very closely into the require-
ments of the case that is responsible. It should be remembered that the
larger instruments are used almost exclusively for photography where
short focus instruments are desirable to obtain negatives of faint objects
with a minimum of exposure time, and that the cost of mounting and
the accessibility of the eyepiece end are increasingly important factors
with increase in aperture. None of these limitations apply to a small
instrument. A reflector 6 or 8 feet long is inexpensive to house and con-
venient to use, and the amateur’s photographic efforts, if any, are likely
to be confined to the brighter objects unless he is blessed with a pre-
cision mounting that few of us can afford. It is perhaps significant that
most of the early reflectors built before the advent of photography were
of f 10 or longer, particularly those of moderate aperture.
Fo, i ell an
a Fy ih
fam wte mm we bee
mat << ©
Planet P, Planets S and T 385
PLANET P, ITS ORBIT, POSITION, AND MAGNITUDE,
PLANETS S AND T
By WILLIAM H. PICKERING.
Although we know the orbit of planet P much better than we did that
of Pluto, formerly known as planet O, yet we can hardly hope to locate
it with quite the same accuracy in the sky. In part compensation, how-
ever, we find that it is probably a much brighter object, requiring a
shorter exposure, which will at the same time eliminate many of the
confusing stars. Furthermore it is located where the stars are fewer,
whereas Pluto, in the position where the writer predicted it in 1919, lay
in the Milky Way itself, when it was later found on the Mount Wilson
negatives. It is thought probable that planet P lies within 2° of its pre-
dicted orbit, thus reducing the number of plates required to photograph
it, if a doublet is used. Even if an ordinary photographic telescope is
employed, the number of plates would not be excessive.
10 530 290 250 210 170 180 90 50 10
+100
_ a.
~<
+ 40
— 20
~ {es6 1es5 1828 1817 1e08 i799 1790 1781 1771 1761
Figure 1.
Revisep Orsit OF URANUS PERTURBED BY NEPTUNE.
As a result of our more accurate knowledge of the elements a, 1, and
3 of its orbit, we can modify our method of research quite materially.
The first step, however, the graphical process, remains unchanged. It
will be recalled that, in our paper entitled “The Next Planet Beyond
386 Planet P, Planets S and T
Neptune” (PopuLar Astronomy, 1928, 36, 143), we began by showing
the general appearance of a perturbation curve. We shall follow the
same procedure here. Figures 1 and 2, taken from that paper, show
the perturbations of Uranus by Neptune and of Neptune by Pluto,
after the original observations had been treated by the sinusoidal
method. The abscissas give the dates and heliocentric longitudes, and
the ordinates the observed perturbations in longitude after the pertur-
bations due to all the known planets have been eliminated. In accord-
ance with this method by making suitable changes in the elements of the
sinusoidal curve we can modify the semi-major axis of the orbit of the
known planet, as well as its eccentricity, and the argument of its peri-
helion in a systematic manner, so as to diminish the sum of the squares
of the deviations, and at the same time render the perturbation curve of
the proper shape, as shown best in the case of the perturbation of
Uranus by Neptune. This perturbation was so enormous, some fifteen
to twenty times the size of those with which we have to deal, that the
180 140 100 60 20 540 500 260 220 186
+5
+4
+5
+1 \ I
Pro
= ¥ _ = | ac
1942 = 1924 1906 18689 # +1871 #41852 1885 18614 1796 19778
FIGuRE 2.
ReEvVISED Orpit OF NEPTUNE PERTURBED BY PLUTO.
accidental errors do not deform it in any way, and it serves to show us
at once the proper shape. e
It will be noted that the theory of this method is quite distinct from
that of the treatment by least squares. In the latter the theory is that all
irregularities in the curve are due to inferior observations and that the
sum of the squares of these deviations should be reduced to its minimum
value. In Figure 3 the upper curve shows the perturbations of Uranus,
as observed at Paris and Greenwich based on Leverrier’s orbit. These
observations and other later ones have been recently treated in an im-
portant paper by Messrs. Morgan and Lyons of the U. S. Naval Ob-
servatory using Newcomb’s orbit, and employing the principle of least
ar
squ
duc
enc
the
an¢
cur
rea
abl
William H. Pickering 387
squares (Astronomical Journal, 1930, 40, 97). I have plotted their re-
sults in the lower portion of Figure 3. It will be seen that their curve
shows the same two perturbations, one at either end, separated by a long
level region that was exhibited in mine (PopuLar Astronomy, 1928, 36,
356), although mine showed the first perturbation much more markedly.
In the sinusoidal theory as here applied on the other hand, certain large
irregularities of the curve are accepted as due to perturbations caused
by unknown planets, while other portions of the curve that appear to be
capable of being straightened out are made as straight as possible, re-
gardless of what may happen to the large irregularities themselves. As
55° 530" 250° 187” 70° sage 267° 175° 80°
+3°
+2"
+1"
— a
—5*
=——
+3°
+2" |
+2° 1
_ t
1940 1920 1900 1860 1860 1840 1820 1800 1760
Figure 3.
PERTURBATIONS OF THE ORBIT OF URANUS.
a result of this procedure we shall find not only that the sum of the
squares in the case of the early observations of Uranus is greatly re-
duced, but that the curve is quite straight for over half of its circumfer-
ence, and that the chief irregularities have now of themselves taken on
the forms of perturbation curves similar to those shown in Figures 1
and 2.
If we believe that the two maxima at the beginning and end of the
curve are due simply to errors of observation, and that the curve should
really be a straight line, then the method of least squares is unquestion-
ably the proper one to employ in deducing it, and we should regret that
388 Planet P, Planets S and T
the errors, especially the later ones are so large. On the other hand, if
we believe that these two maxima are genuine and due to perturbations
of some unknown outer planet, then the method of least squares should
be rejected, and the sinusoidal method of reduction should be employed
in its place. That is why I used it in the case of Pluto, and shall now
use it again in the case of planet P. Nevertheless the two methods do
give analogous results as we shall presently see, for it is almost impossi-
ble to conceal a perturbation maximum, although it may be somewhat
shifted in longitude, and its amount considerably modified, if other
methods of reduction are employed.
6? 2° sag? 300° 260° 227 160° 1a loo? od
+a"
J 7.
Pe ° > ae e
anes er \y “A
e
eN
or x =
\
A
e?
~— 3
ae
«
—- oO
1658 1648 1836 1628 1619 1810 1601 1792 17&4 1776
Figure 4.
First PerturRBATION OF URANUS DUE TO PLANET P.,
In Figure 4 a portion of my early curve is shown plotted as dots upon
an enlarged scale, and the same portion of the Washington curve, con-
sisting of small circles, is plotted upon it. This latter we see has greatly
flattened the results, that being the object of its computers. I have
grouped certain similar observations of my early curve, based on
Leverrier’s, and joined their centers of gravity. A few very discordant
observations have been rejected. Since I believe that this portion of the
curve represents a genuine perturbation of Uranus produced by the
same unknown body that is producing the present discordances, I feel
that it is a mistake to flatten it out. However, although flattened in the
Washington curve, the perturbation has not been wholly destroyed, but
its shape no longer resembles a true perturbation (see Figures 1 and 2)
and its apex has been removed some 70° by artificially diminishing the
deviations that occurred between 1800 and 1825. The sinusoidal re-
duction on the other hand leaves the longitude of the apex nearly as
or
sh
Ww
pe
tic
re
in
re
William H. Pickering 389
originally observed at 1810 (see upper curve of Figure 3) while the
shape of the curve is the same as those shown in Figures 1 and 2, which
we know were actually due to perturbations, because in both cases the
perturbing planet is now known.
Figure 5 gives a similar large scale drawing of the second perturba-
tion shown in the lower curve of Figure 3. The dots as before give my
reductions of the observations recorded in the upper curve of that draw-
ing based on Leverrier’s orbit. The small continuous circles show the
results of Messrs. Morgan and Lyons, discontinuous it will be noted in
1896, and the dotted circles some provisional results by Messrs. Ham-
Jf. sac? 300° 260° 220° 180 140? loo” oad oe
+
+3°
+1°
Ws iA“
2
o° aaaein —-s
o
e
e
é ‘
— 1°
Sod
*
1932 1922 19129 1893 168 «(1876 1867 156 = (18A8
Figure 5.
SECOND PERTURBATION OF URANUS DUE TO PLANET P.
mond and Morgan, kindly sent me by the Superintendent of the Wash-
ington Observatory (Astronomical Journal, 1930, 40, 85). Their re-
duction of the observations begins with the year 1894, but the earlier
observations merely follow a course midway between the dotted and the
continuous lines of Figure 5, and it seemed undesirable to clog the
figure with too much material. They show a maximum at 300°, but
not so marked as that at 350°. The level line of observations nearly
coinciding with ordinate 0” is well shown in both series. The inclined
crosses represent the observations made at Greenwich, and published in
Monthly Notices, 1929, 89, 261, and the vertical ones at the end some
provisional results, for which I am indebted to the Astronomer Royal.
It will be noticed that all three series, Washington, Greenwich, and my
own reduction, indicate that a pronounced maximum occurred in 1912,
in heliocentric longitude 300°, and that this was followed by a smaller
maximum at 350°, much less marked, although Washington makes it
higher than Greenwich.
Attention should be called to the fact that the abscissas of the four
390 Planet P, Planets S and T
perturbations shown in Figures 1, 2, 4, and 5 are all on the same scale.
The four perturbation curves therefore each have about the same length,
measured on the orbit of the perturbed body. Uranus moves so swiftly,
however, compared to the leisurely moving P, which is from three to
four times as remote, that we should expect it to escape from its per-
turbing power more quickly than the bodies in the first two curves,
where the perturbing body is only one and a half times as remote, and
therefore follows it further. The first two perturbations extend through
180° and 160°, but the last two through only 130°. The curve itself,
therefore, without any computation whatever, gives us a hint as to the
considerable distance of the unknown body. The dots in Figure 5 give
a better shaped perturbation curve than the circles or crosses, doubtless
for the reason already explained that I made no attempt to artificially
modify the curve by weighting the observations. It was seen that the
interval between longitudes 20° and 240° by a simple sinusoidal reduc-
tion would come out a nearly straight horizontal line, and as it was a
plausible hypothesis that there were no large unknown planets to per-
turb Uranus in that part of the sky, an effort was made to make this
part of the orbit as straight and as horizontal as possible, while the
two perturbations were left to take care of themselves. As a result they
both showed themselves to be true perturbation curves without any
attention from the computer whatever.
Admitting that in the long level region extending through 220° of
longitude, no large unknown planet disturbed Uranus, we can thus see
how accurate were the observations as far back as the first half of the
last century. It is certain that modern observations cannot be inferior
to them, and it is therefore certain that the perturbation that now affects
Uranus is a real one. It must be pointed out, however, that while it is
true that no large planet perturbed Uranus in that portion of its orbit,
yet there should have been shown a small perturbation due to Pluto, be-
tween the years 1853 and 1863, and amounting to about half a second of
are (PorpuLar Astronomy, 1931, 39, 3). It appears, therefore, that I
unwittingly flattened my curve a little bit too much. Such small per-
turbations, however, are really beyond our capacity to detect at present.
At that time I believed that the perturbation shown in Figure 4 in 1841
was the real one due to Pluto, and so was led to an erroneous distance of
that body. This fortunately did not affect its location in the heavens.
Returning to Figure 5, we see that Washington was even more neglect-
ful of Pluto than I, for they left a minimum in place of a maximum
between 1853 and 1863.
Although the scales of the abscissas of Figures 1, 2, 4, and 5 are
identical, the scales of the ordinates it will be noted are very different,
especially for Figure 1. Figures 2 and 5 are on the same scale, but in
Figure 4 it will be seen that even if we reject the first ten observations
as erroneous, which I believe should be done, the maximum perturba-
tion is still 6”, while for the second perturbation in 1912 it is only 3”.
This difference at once suggests a rather high eccentricity of the orbit
William H. Pickering 391
of P, and that the planet was nearer to Uranus at the first perturbation
than it was at the second. In my paper “The Orbit of Uranus” (Popu-
LAR ASTRONOMY, 1928, 36, 360) it was suggested that the perturbation
in longitude at 350°, Figure 5, was due to a moderate sized planet which
we called S, somewhat nearer as well as smaller than P. If we continue
the slope of the larger perturbation to longitude 350°, it will cross that
longitude at 0”.7, and will allow the perturbation due to planet S a max-
imum height of 1”.3. Giving the right hand slope of the latter pertur-
bation a proper inclination will leave the height of the maximum of
planet P equal to about 2”.2. There are a few minor peculiarities that
may be mentioned here, on which all four of the perturbation curves
agree. They are all sharply pointed at the top, and the left hand side
is steeper than the right. In Figure 4 this latter is not marked, but is
still true. The curves are not so steep near the top, on either side, as
lower down, this change of slope giving them all a somewhat similar
shape and appearance.
Having now given the planetary data on which we shall base our
further deductions, we will turn to the cometary evidence. This matter
has been already taken up at some length in PopuLar Astronomy, 1928,
36, 417, and 1931, 39, 321. It is only necessary therefore to touch on
the subject very briefly here. In the case of the 21 comets belonging to
class C, those whose aphelion distances lie between 75.5 and 209, 16 be-
long to type P, those whose aphelia lie within 20° of a great circle of the
sphere. The zone thus described covers one-third of the total area of
the sky. Five aphelia lie outside of this zone, four of them being quite
remote, and evidently these comets are in no way related to the others.
That this arrangment is not due to chance we can readily see, if we con-
sider that two of the 16 selected aphelia are required to define the zone,
and that of the remaining 14 orbits of the group, the chance expressed
by 3 raised to the 14th power is a considerable number,—a little short
of five million. This number will, however, be reduced appreciably by
the five discordant comets. The computation is easily made by a simple
formula, but as it would involve considerable time to compute it, it is
quite sufficient to say that the chance against the grouping of the 16
comets together being due merely to accident is many thousands to one.
In other words they are certainly related to one another, just as are the
comets in Jupiter’s family. Such being the case, the node and inclina-
tion of the great circle are obviously those of the planet. Since these
comets are coming at the rate of at least one in every nine years, and
their average period is 480 years, there must be over 50 of them. More-
over we only see those whose perihelia lie within the orbit of Mars, and
some may well have perihelia extending to 10 or 20 times that distance,
doubling or trebling their number. For comparison we may state that
of the 41 comets formerly associated with Jupiter, only 22 have been
known to return within the last 25 years, and it is improbable that we
shall ever again see the others. In other words, we may say that the
members of Jupiter’s family are constantly changing, and that 22 is
392 Planet P, Planets S and T
perhaps a fair average number at any one time. The implication is that
planet P is a very massive body. In the first of the above mentioned
papers it is shown in the case of Jupiter, Saturn, Uranus, and Neptune
that the shortest cometary aphelion distance associated with them is
nearly identical with the mean distance of the planet. This is of course
what we should expect, because it is obvious that a planet cannot per-
turb and capture a comet unless in some portion of its orbit it comes
near to the planet. We may make the following comparison of these
distances :
PLANET MEAN DISTANCE CoMET
Jupiter 5.2 4.1
Saturn 9.5 9.7
Uranus 19.2 19.6
Neptune 30.1 30.0
Jupiter is so massive that it naturally can hold a comet at a greater
distance than the other planets. The shortest cometary aphelion associ-
ated with planet P, as far as we know, is 75.5 units for comet 1857 IV,
and we shall take that number as the mean distance of P, although we
clearly know so few of the comets that are associated with it. The next
shortest aphelion distances are as much as 87.9 and 89.0. The cor-
responding period is 656 years. The adopted node is 351°, and the in-
clination 37°. Bode’s law gives so accurately the distance of Pluto,
38.2 to 39.6, that it is interesting to note that it agrees well also with
our assumed distance of ?. According to it the distance should be 77.2.
Although I have stated several times in print that the maximum per-
turbation of the known planet does not come at the time of its conjunc-
tion with the unknown, and that my method of locating the unknown
has nothing whatever to do with the conjunction, yet, as I am aware
that even prominent astronomers sometimes make that mistake, I wish
to repeat the statement here. In the case of Pluto it was in conjunction
with Neptune in 1891, but the maximum perturbation of the latter did
not come until eleven years later. It is obvious that, if the unknown
planet is beyond the known, at the time of the maximum _perturba-
tion it will be several degrees behind it. In order to locate the unknown,
we should know this number. Let us take the plane triangle SUN, and
applying it to the discovery of Neptune, we found by the early measures,
after treating them by the sinusoidal method, at the time of the max-
imum perturbation of Uranus, that the angle at S was —8°.2, indicat-
ing that Neptune was behind Uranus by that amount. The angle at U
was 157°.9. In the case of Neptune and Pluto, after the orbit of the
latter was well determined, it appeared that at the time of the maximum
perturbation of Neptune, Pluto was —12°.4 behind it. The obtuse angle
varied through a much greater range. The determination of the former
angle is the only step in our method of location of an unknown planet
that may properly be described as empirical, and the small difference
between the two angles, 4°.2, was gratifying. In the case of planet P, I
place double the weight on the result obtained with Pluto that I should
William H. Pickering 393
with the other, and have therefore decided that the angle at the Sun be-
ween Uranus and P was —11°.0 in longitude.
It is regrettable that P has produced no observable perturbation
hitherto of the planet Neptune. Neptune when it was discovered in
1846 was some 70° ahead of P, and since their overtake period is 220
years, no conjunction even with Neptune can be expected before 2020.
Having only two perturbations of Uranus on which to depend, it might
at first glance be supposed that we did not have sufficient data on which
to compute an elliptical orbit, but it must be remembered that we also
9°
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27°
Ficure 6.
THe Orpits oF PLuTO AND PLANET P.
have the semi-major axis, and the ratio of the extent of the two pertur-
bations. This ratio unfortunately, however, does not help us as much
as it usually should, because both perturbations are interfered with by
the assumed planet S. The two maxima occur far enough apart in
Figure 5 to enable us to determine their relative importance, but in
Figure 6 they coincide. We cannot tell therefore how much of the
6” is due to P. If we assumed that the same ratio held as in 1912, the
two perturbations of P were for 1812 3”.8, and for 1912 2”.2, ratio 1.73.
On the other hand if we make no allowance at all for S then the two
394 Planet P, Planets S and T
perturbations of P were 6”.0 and 2”.8, ratio 2.14. Whatever ratio we
adopt will affect chiefly the value of e, and that is not of much conse-
quence since it gives little aid in finding the planet. We shall for the
sake of the computation adopt the ratio 1.90, which gives us for e the
value 0.265,—a not improbable figure, and one not very different from
that found for Pluto, of which the two best determinations so far pub-
lished are 0.254 and 0.249. Our ratio 1.90 should be approximately
inversely proportional to the square of the distances of P from Uranus
at the times of its two maximum perturbations, measured on the plane of
the ecliptic. In Figure 6 are shown the orbits of the four outer planets.
The smallest circle shows that of the earth.
TABLE L.
ELEMENTS OF THE OrsBIT OF PLANET P, AND OTHER DATA,
Elements Other Data
a Semi-major Axis 75.5 Magnitude, if like Pluto 15
e Eccentricity 0.265 Angular Diameter 122
i Inclination sf” Diameter in miles 44000
$3 Ascending Node gol” Present Annual Motion +0°42
w Argument of Perihelion 170°5 Parallactic Daily Motion —4378
P Period 656 Orbital Daily Motion +49
T Date of Perihelion 1742 Present Longitude 29825
Other Data Present Latitude —30°9
q Perihelion Distance 55.5 Present Right Ascension 20" 40™
Aphelion Distance 95.5 Present Declination —50°
Present Distance 85.0 R.A. 10° or 20 years back 19*'53™
mw Longitude of Perihelion 172°9 Dec. 10° or 20 years back —55°2
# Mean Annual Motion 0°549 R.A. 10° or 20 years hence 21"14™
E Epoch 1932.0 Dec. 10° or 20 years hence —45°3
m Mass 49.6 Maximum perturbation in 1912 272
Magnitude, if like Neptune 11.2 Date of Opposition in 1931 Aug. 1
In Table I are given the elements of the orbit of P, and other data re-
lating to the planet and its orbit. It will be noticed that its descending
node coincides with its longitude of perihelion within the limits of the
probable errors of the computation. We have already remarked that a
planet that controlled so many comets, more apparently than any other
planet in our system, must be very massive. We now find from its per-
turbations of Uranus that its mass is half that of Saturn, 94.9, three
times that of Neptune, 17.2, and fifty times that of the earth. It is there-
fore the third planet in the solar system. When I first recognized its im-
portance, from its comets, some twenty years ago, I mentally reserved
for it the name Pluto as the son of Saturn, and the brother of Jupiter
and Neptune, but unfortunately that small object planet O came round
and perturbed Neptune some ten years before the liesurely P arrived
and perturbed Uranus, and so received the name. Pluto should be re-
named Loki, the god of thieves! A suitable name for P will now indeed
be difficult to find when that planet is discovered.
Two values are given for the expected magnitude of P, one if in den-
sity and albedo it resembles Neptune, and the other if it resembles Pluto.
The latter is not thought probable. As we retreat from the Sun among
William H. Pickering
the larger planets, after passing Jupiter, we find that both the density
and albedo tend to increase. The diameter, angular and linear as here
given, is based on a density supposed identical with that of Neptune.
Its diameter thus proves to be so large that it should present a clearly
defined disk in our larger telescopes. It is so remote that we notice that
its parallactic motion at opposition is nine times that of its real motion
in its orbit. It is believed that the planet should certainly lie within 2°
of its orbit north or south, and within 10° of its computed location. To
facilitate finding it, I have indicated the orbit by giving the computed
position of the planet 20 years ago, and also 20 years hence. The
maximum perturbation of Uranus in 1912 is that given after allowing
for the perturbing force of planet S in that year. The date of opposi-
tion advances half a day every year.
Uranus has now been observed accurately through 147 years, or 1.75
revolutions. This interval is ufficient for it to have passed every un-
known planet whose mean distance exceeds 33.3 units, at least once.
No large planet therefore, unless extremely remote, can have failed to
have left its mark on the orbit of Uranus.
PLANET T.
We now come to the rather interesting question, are there other, small,
remote, dark planets analogous to Pluto, and in similar orbits, or on the
other hand can we safely reject as illusory the little apparent perturba-
tion following the large one in both Figures 4 and 5? If genuine we
should naturally suppose that both of the small perturbations were
caused by the same body, but this certainly cannot be the case, the diffi-
culty being that both occur in the same longitude 350°. They cannot
be due to a small dark star comparatively near at hand, nor to an outer
planet moving nearly due north or south, because Neptune passed this
same longitude in 1857 and showed no appreciable perturbation. They
cannot be due to an unknown planet revolving in a period of one-half
of that of Uranus, because in that case the perturbations would take the
form of depressions instead of elevations. They must therefore be due
to two distinct bodies. There can scarcely be any doubt at all of the
existence of the one which perturbed Uranus in 1924. The observations
of the earlier one shown in Figure 4 are so accordant that we should
feel little doubt of it either were it not for the fact that its duration in
longitude, as shown by the observations, certainly cannot exceed 120°,
and might be as short as 80°. This would imply that it was very remote
like P. This may of course be true, and we will call it provisionally
planet T. If it were moving in a circular orbit, in the same period as P,
Uranus would pass it once in 96 years, and 96 added to the date of the
perturbation under discussion, 1841, brings us to the year 1937. An
elliptical orbit might give us a somewhat longer or shorter interval, so
we can make no definite statement, but we see that such a planet is pos-
sible. It cannot, however, be very much more remote than P, or Uranus
would have passed it a second time already. The sooner it appears again,
396 Planet P, Planets S and T
the more remote and massive it will be. Until it again perturbs Uranus,
as far as that planet is concerned it will be impossible to set any lower
limit to its distance from the Sun. This is about all that we can learn
from Uranus, but Neptune will give us a little more information. By
Figure 4 we see that Uranus received the maximum perturbation from
T in 1841, in longitude 350°, and since T must have been about 11° be-
hind it, 7 must have been in longitude 339°. It appears that Neptune
in 1841 was only 25° behind that, in longitude 314°, and we shall
assume now that it was overtaking T as rapidly as possible. It has not
overtaken it as yet, however, sufficiently to show any perturbation of the
Neptune curve. Neptune’s present longitude is 155°, and it has there-
fore travelled 201° in ninety years. In case the conjunction of Neptune
and T occurs in the present year, Neptune would surely have shown
some perturbation by this time. Since it has not done so as yet, it
seems that Neptune has not gained even 25° in ninety years. JT must
therefore have moved more than 176° in that time, and its period must
be less than 188 years, corresponding to a distance of 32.8 units. There
is of course nothing impossible in the existence of a planet with a period
so nearly identical with that of Neptune. Indeed its orbit might well lie
between that of Uranus and Neptune, there is plenty of room for it there,
and the only oppositon that we can raise to the idea is the fact that the
base of the perturbation curve of Uranus appears to be too short. In
conclusion we may say, therefore, that we can hardly as yet accept T as
a real planet until it presents further evidence of its own existence, and
that we must leave for another, or possibly a future generation of
astronomers.
PLANET S.
In my paper on “The Orbits of the Comets of Short Period” (Popvu-
LAR AsTRONOMY, 1928, 36, 280), I suggested, based on an isolated group
of 4 comets, that they might perhaps be associated with a rather massive
unknown planet that I designated as planet S. Based on the shortest
aphelion distance of the group, 47.6, I suggested that its period would
be 333 years. More accurately stated this should be 328 years. In my
paper on “The Orbit of Uranus,” in PopuLar Astronomy, 1928, 36,
360, I pointed out that, with a period of 333 years starting with the max-
imum perturbation which this planet would produce on Uranus in 1924,
the previous one would fall near the summit of the large perturba-
tion due to P in 1812. By means of the later planetary observations of
Uranus now in our possession we may say that the small perturbation in
Figure 5 is undoubted, and that the large perturbation in Figure 4 gives
us therefore an interval of 112 years. Adopting this figure as the over-
take period of Uranus and S, and 84 years as the period of Uranus, then
the period of S turns out to be 336 years, and its corresponding distance
48.3 units. The resemblance of the two diverse determinations of the
period and distance is at least suggestive. It is clear that S cannot be
more remote than this distance, or its perturbation of Uranus would
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William H, Pickering 397
have appeared between the two maxima of Figure 4. If the distance of
S is not about 48 units, then it must be less than 35, or its perturbation
would have appeared between the years 1784 and 1812. That is to say
it must be nearer than Pluto unless its orbit is very eccentric, in which
case it might be a little more distant. There are, therefore, two possible
explanations of what is almost certainly an unknown body of somewhat
more than terrestrial dimensions. One is that it is moving in an orbit
analogous to that of Pluto, and the other that it is moving in an orbit
about 20 per cent larger. In the latter case it may be nearly ten times
as massive as Pluto, in the former perhaps two or three times. Neptune
since its discovery has been constantly ahead of S, and so can throw no
light on its position.
The second maximum perturbation of Uranus is so recent, that S
cannot have moved far in longitude from the position that it held at that
time in 1924, 350° — 11° or 339°, using the same correcting angle that
we have for P and T. If we adopt the greater distance, 48, that was
confirmed by the comets, its mean annual motion will be 1°.10. If we
adopt the maximum lesser distance 35, its mean annual motion will be
1°.74. Its present longitude, after seven years, on these two theories is
therefore either 347° or a little over 351°, depending on how much
shorter its mean distance is than 35 units. This, therefore, gives a com
paratively narrow range over which it is necessary to search for it.
There is no way of computing the latitude, and hence the declination,
but as in the case of Pluto, I can give a hint with regard to it, and it is
to be hoped that this time the hint will not be given weight zero. It is
very certainly to the north of the ecliptic, and probably at some distance
from it. This result is based on the northerly declination of Uranus as
eiven in the Washington observations (Astronomical Journal, 1930, 40,
87) and during the last few years confirmed less markedly at Greenwich
(Monthly Notices, 1929, 89, 261), and in a private letter from the
Astronomer Royal as follows: for 1928.9 A8 0”.0, 1929.9 +-0".2, 1930.9
-0”.7. These last results he states are only provisional. The Washing-
ton measures, also provisional, are in general for some reason about 1”
higher than those of Greenwich.
Turning now to the comets, there are but four whose aphelion dis
tances, ranging from 47.6 to 59.1 might connect them with planet S, and
one of these is ruled out by the fact that the position of its aphelion on
the celestial sphere is distant more than 50° from the great circle pass-
ing approximately through the other three. Little weight therefore
can be given to the information derived from this source, until more
comets having approximately this aphelion distance arrive. Such comets
are distinctly wanted. Such evidence as we have, however, indicates
that the inclination of the orbit is 30°.5, or a little higher than halfway
between that of Pluto and P. The node is 271°. If the planet is in
longitude 347°, as we think most likely, the cometary aphelia would in-
dicate that it is at present located 30° north of the ecliptic. Although
its mass appears to be greater than that of Pluto, yet since we have no
398 Planet P, Planets S and T
satisfactory evidence as to the eccentricity, or the argument of the peri-
helion of its orbit, we can only say that its brightness is probably about
the same as that of that planet. The middle one of the three positions
is thought to be the most probable location. The other two indicate the
effect of giving the orbit a higher or a lower inclination, or of shifting
the node. The line joining the three is perpendicular to the planet’s
orbit.
TABLE II.
LocATION OF THE PLANET S For 1932.
Longitude Latitude R.A. Dec.
347 +20° ge 4i" +13°3
347 +-30° Egg aa -+22°4
347 +40° 22°04" +31°4
The positions are given for 1932.0. The declination is undoubtedly
much more uncertain than the right ascension. I state this definitely,
because in the case of Pluto, those who searched for it in 1919 extended
their search unnecessarily far on both sides in right ascension, about
15°, yet always kept close to the ecliptic in declination, in spite of our
statement that the inclination of the orbit was probably about 15°, that
the planet had been in the south, but was now moving northerly, and
was at present not far from the ecliptic. They thus missed the planet
in their search at that time by less than two degrees in declination. Had
I been informed of the search, I should have saved them from taking
several unnecessary plates in right ascension, from searching north of
the ecliptic in declination, and should have informed them that, since it
was impossible to compute the declination, the latter was much more
uncertain than the right ascension, and therefore they should look
towards the south, whence the planet was believed to have come.
In general I should like to state very clearly that, when a search is be-
ing made for any unknown body, be it planet or satellite, and it is not
at once found, the computer should always be informed of the fact, and
his advice asked for in that case. It would seem indeed fairly obvi-
ous that, if the search is worth making at all, first, no time should be
absolutely wasted upon it, and second, the computer would certainly
know far more about his own computations than the searcher. Indeed
it is only fair to the computer that, if his predictions are on trial, he
should at least be warned of the fact. It would certainly be far better
for both parties, for I know by experience how tiresome and dis-
appointing it is to look over a stack of plates and find nothing. And yet,
as in the case of Pluto, a single word from the computer might have
turned failure into a brilliant success.
PRIVATE OBSERVATORY, MANDEVILLE, JAMAICA, B. W. I., Jury 8, 1931.
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The November Metcors in Maya and Méxican Tradition
THE NOVEMBER METEORS IN MAYA AND
MEXICAN TRADITION
By STANSBURY HAGAR.
Before the arrival of the first Spaniards in Mexico, over 400 years
ago, and probably much earlier, the Mexicans told of certain stars called
Tzontemocque or [Falling Hairs, which fell from heaven to earth with
the Lord of the Dead.’ Their fall was commemorated annually in the
Quecholli festival, said to have been held towards the end of October.
This festival, and the falling of the stars, was associated with the end
of the world. As the ritual features of all the annual Mexican festivals
Figure 1.
DESCENDING METEOR IN MEXICAN Copex BoraiA. (After Seler.)
were concerned with annual events, it seems evident that the fall of the
Tzontemocque was also believed to occur each year. The Lord of the
Dead governed the Festival of the Dead preceding the Quecholli, during
which the spirits of the dead were supposed to return to earth from the
land of Souls in the sky. No doubt they were believed to have been
accompanied by their deity whose fall is mentioned in the ritual. On
sheet 8, of the Mexican Vaticanus 3773, and in the Borgian and other
codices, these Stars of the Falling Hairs, are depicted falling from the
sky to earth accompanied by many other stars, further identified by the
conventional star symbols beside them.
*Explanation of the Codex Telleriano Ramensts, fol. 4. v. and in Kingsbor-
ough Mexican Antiquities, Vol. 6, pp. 101, 127, 130, Brasseur de Bourbourg in
Landa, p. 37, note 3.
400 The November Meteors in Maya and Mexican Tradition
The Vaticanus Codex antedates the entrance of the first Spaniards
into Mexico and depicts traditions much older than that date. From
these facts it seems reasonably certain that the Tzontemocque were
November meteors, whose falling hair referred to the fiery trails left
behind them. The maximum fall of several meteor groups occurs in
November. That of the Leonids, originating in Leo, occurred on Octo-
ber 13 in 902 A.D., and October 24 in 1533,? so that, when the Spaniards
entered Mexico in 1519, the fall of the Tzontemocque was celebrated on
the day when these Leonid meteors attained their maximum fall, or very
close to it. But the Mexicans seem to have distinguished between the
different meteor groups, for they refer to the fall of a Tzontemoc on
the day One Eagle which pertains to Taurus and would seem, therefore,
to refer to Taurid meteors. The end of the world would naturally be
associated with the memory of one of the great meteoric showers dur-
ing November, when all the stars seemed to fall from the sky.
Ficure 2.
TAurtp Meteor oN Maya ZoptAc AT ACANCEH, YUCATAN. (After Seler.)
(Downflying figure at right of top row.)
) I
At Acanceh in Yucatan a Maya Zodiac was placed on the stucco
facade of a mound, probably long prior to the coming of the Spaniards.
It was probably at least 600 years old when it was exhumed. On this
Zodiac, which represents the signs in regular sequence, the position of
Taurus is occupied by two panels, the lower of which represents the
rattle of a snake. It is Tzabek, the Rattle Asterism, our Pleiades. The
upper panel contains a downflying semi-human or ape-like figure. Be-
side his tail are star symbols and above his head spears or arrows, im-
plements of war, which, in the Quecholli festival, represent the end of
* Encyclopedia Britannica, Meteors; “Meteors,” Charles P. Olivier, 1925, p. 36.
* Hagar in American Anthropologist, NS. Vol. 16, p. 89.
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Planet Notes 401
the world, marked by the fall of the Tzontemocque.* This Maya figure
also probably refers toa Taurid meteor emanating from Taurus in
November when that asterism is near the meridian.
Some of the plains Indians of the United States were accustomed to
mark the passing of time by drawing on a buffalo skin, some event that
distinguished each winter. All these winter counts for the year 1833
depict a group of falling stars, interpreted as, ‘the stars fall,” “storm of
stars,” “it rained stars,” “the stars moved around.” Especially note-
worthy was the winter count of Chief Long Dog of the Yankton
Dakotas.*
The end of the cycles of many peoples in November and their expec-
tations of the destruction of the world at that time, was probably like-
wise associated with the November meteors.°
*Col. Garrick Mallery in Bureau of American Ethnology, Vol. 4, pp. 90-138.
*See “New Materials for the History of Man,” by Robert Grant Haliburton,
Toronte h 1920.
PLANET NOTES FOR SEPTEMBER AND OCTOBER, 1931
By CLIFFORD E. SMITH.
The Sun will be moving southeast from the central part of Leo to the eastern
part of Virgo. On September 23, at 6:00 Pr.m., C.S.T., the sun will cross the celes-
tial equator which marks the beginning of fall. There will be two partial eclipses
of the sun during this period; one, on September 12, will be visible in Alaska, and
the other, on October 11, will be visible southwest of South America. The right
ascension of the sun will change during this period from about 103 to about 14
hours, and the declination will change from about +9° to about —13°.
The phenomena of the Moon will occur as follows
Last Quarter Sent. Sat 1 aw. C.S.T.
New Moon 11 “ 10 p.m. 3
First Quarter 18 “ 3 pM.
Full Moon ae“ 2 PM.
Last Quarter Oct. 4 2 P.M.
New Moon 11 7 AM.
First Quarter 18 3 A.M.
Full Moon 26 “ SAM.
Perigee Sept. 12 “ 11 a.m
Oct. 10 “ 10 p.m.
Apogee Sept. 26 “ 9 p.m.
Oct. 23 “ 11 P.M.
On September 26 there will be a total eclipse of tl
in most of the eastern hemisphere, but not in the western hemisphere excepting the
eastern part of South America.
moon which will be visible
Mercury will be moving with an apparent western motion in eastern Leo until
September 13; then its motion will become easterly, and it will move across Virgo
to western Libra. At the beginning and end of this period its position will be
near that of the sun, and during the middle of this period it will be a morning
402 Occultations
star of about zero magnitude, rising about an hour before the sun. Greatest
elongation west will occur on September 21, and superior conjunction on Octo-
ber 18.
Venus will be near the sun in apparent position during the early part of this
period since superior conjunction will occur on September 8, but at the end of
this period it will be an evening star of magnitude about—3.5 setting about an
hour after the sun. Its apparent motion will be direct.
Mars will be in the early evening sky but of even less interest than during
July and August since its distance from the earth has been increasing, and since
its apparent position will be approaching that of the sun. Mars will be moving
from central Virgo to eastern Libra, and on the first of October it will set about
two hours after the sun.
Jupiter will be a morning star in central Cancer of magnitude about —1.5,
and its apparent motion in the sky will be direct. At the end of this period it will
rise soon after midnight. Conjunction with the moon will occur on September 9
and on October 7.
Saturn will be in the evening sky in eastern Sagittarius, and it will be of about
zero magnitude. Its apparent motion will be retrograde until September 21 and
after that direct. Quadrature east of the sun will occur on October 11, and thus
during the middle of October it will be on the meridian about 6:00p.m. Con-
junction with the moon will occur on September 20 and on October 17.
Uranus will be in eastern Pisces and will be visible practically all night long
during this period since opposition with the sun will occur on October 11. Its
apparent motion in the sky will be retrograde. Conjunction with the moon will
occur on September 28 and on October 25.
Neptune will be near the sun in apparent position. Conjunction with the sun
will occur on October 29.
OCCULTATIONS
OccuLTATIONS VISIBLE IN LonGiITUDE +72° 30’, LatirupE +-42° 30’.
(Contributed by the office of the American Ephemeris.)
—_———1IM MERSION——— EMERSION
Green- Angle E Green- Angle E
Date wich from wich from
1931 Star Mag. oF i a b N wc: a b N
Sept. 4 27 Tau 37 6 247 0.0 +2.8 27 7 25.1 —18 +0.8 278
4 28 Tau 5.2 6416 +08 +40 3 7 20.00 —2.7 —0.6 302
6 107 BAur 65 4 64 +0.2 +08 110 450.7 +06 +1.8 227
8 c Gem 55 7 20 —04 +01 133 7 45.0 +03 +2.2 233
22 56B.Cap 63 0206 —13 +19 17 118.8 —28 —0.7 296
24 50 Aqr 59 6256 —08 —05 66 7 320 —0.2 +01 224
26 20 Psc 5.6 4360 —09 +1.7 26 5 52.4 —18 0.0 250
27 44 Psc 61 0314 —05 +22 49 1 424 —10 +1.8 240
Oct. 1 n Tau 3.0 14216 —05 404 35 14598 +09 —2.4 310
2 x Tan 5.3 329.0 —04 +1.5 87 4 29.2 —0.2 +2.2 227
3 34 EB.tan 64 5 39 0.0 +25 45 6 46 —1.3 +08 283
6 A Cnc 5.9 6249 —03 +07 114 7 236 —0.4 +1.5 262
8 37 Leo 5.5 7 49.5 0.0 +0.9 105 8 46.0 —0.4 +0.4 298
27 27 Ari 64 5167 —18 +12 58 6 43.0 —1.7 +0.6 238
28 66 Ari 6.1 11 40 —08 +02 44 11548 +03 —22 295
29 x Tau 5.3 12 22 +09 —4.1 149 12 31.0 —13 41.5 204
Oc
Se
On
Occultations
403
OccuLTATIons VisIBLE 1N LoncitupE +91°, Laritupe +40°.
IM MERSION— - ——EMERSION———
Green- Angle E Green- Angle E
Date wich from wich from
1931 Star Mag. C.T a b N om a b N
h m m m ° h I I m °
Sept. 4 104 B.Tau 5.5 5 338 135 $332 174
4 27 Tau a7 6 35. 340 6 42.0 327
17 b Sco 4.7 1 30.2 179 1 46 206
21 56 B.Cap 63 23 45.8 i a) J 0 29.6 - o< a
24 50 Aqr 59 6 77 —1.0 +06: 42 7 225 10 —0.2 241
26 20 Psc 5.6 4 24.5 - ee > ay ie o=. toe
27 44 Psc 6.1 0 21.6 0.0 +21 44 1 23.0 —0.5 +1.7 254
Oct. 1 i7 Tau 3.8 1257.2 —14 +10 39 13516 —0.2 —28 300
1 n Tau 3.0 1412.1 —06 —06 67 1513.4 +01 —1.5 277
2 x Tau 5.3 3 25.4 +03 41.5 69 4 22.4 0.0 +1.6 249
$ $54 B.Tau 64 5 65 +11 +31 16 5 38.6 14 —0.2 312
5 134 B.Gem 65 4 52.0 - .. 164 5 5.4 ee » ioe
6 A Cnc 5.9 6226 +03 +09 99 7 16.8 0.0 +1.0 275
27. 27 Ari 6.4 446.7 —09 +26 32 6 35 2 +0.7 255
28 ¢ Ari 48 1388 —0.7 41.0 111 2 18.4 +06 +28 192
28 «66 Ari 6.1 10 46.4 12 —04 68 11574 —06 —1.3 267
30° 354 B.Tau 64 13 52 —10 05 67 14 3.6 0.1 —2.2 301
OccuLTATIONS VISIBLE IN LoncitupE +120°, Latirupe +36°.
Sept. 1 m™ Psc 5.6 13 47.2 —08 +30 10 1439.5 —1.5 —2.7 286
2 19 Ari 58 6 25 —0.2 +1.5 82 6 58.8 0.0 +2.2 213
21 A Ser 49 6359 —0.7 +02 46 7 44.9 10 —1.0 263
24 50 Agr ao «€§65 32 eo ~. aoe 6 13.8 . ae
24 182 B.Aqr 62 9276 —16 —1.4 94 10 22.1 0.2 +16 194
300 47 Ari 5.8 14 448 —1.5 29 16 = 15 21.5 0.1 —4.2 312
Oct. 1 16 Tau 5.4 12 36.7 i ae : 3 ga ao
1 17 Tau 3.8 12 0.9 21 +13 56 = 13 28.0 2.0 0.8 266
1 20 Tau 41 3 223 - .. 359 13 43.9 .. 328
1 23 Tau 43 13 3.3 —21 —3.2 124 14 13 19 +2.7 206
1 m Tau 3.0 13 44.6 16 —1.5 101 14 59.3 —1.4 0.3 234
5 v Gem 43 2552 2.0 +40 47 13 44.8 —1.9 3.9 335
25 171 B.Psc 63 2 84 0.6 +18 75 3123 —0.5 +23 213
28 «66 Ari 61 9542 —23 +03 77 11238 19 +0.5 239
30 354 B.Tau 6.4 12 28.1 18 —1.6 111 13 47.8 1.8 —03 250
The quantities in the columns a and b are given for the purpose of making
these predictions useful for any place within 200 miles of the point indicated.
The procedure is as follows: Subtract the longitude of the point given from
the longitude of the place in question;
count, by the quantity under a for the star
latitude, 1
Greenwich C.T.,
nomenon at the place of observation.
necessary to subtract five hours;
Date
1931
Sept. 21
24
Aug. 26
Sept. 21
24
ising b; apply th
VISIBLE AT OMAHA
Star
» Sagittarii
50 Aquarii
VISIBLE
x Capricorni
A Sagittarii
182 B. Aquarii
e sum of th
Mag. ok ag ig
h m
8 5 25
5.9 6 04
AT Mount HAMILTON
5.3 10 27
4.9 6 35
6.2 9 23
multiply the result, taking t
to be obse
e products
and obtain the predicted Greenwich Civil
To obtain Eastern
Central Standard
signs into ac-
with the
tne
rved; similarly,
with its proper sign, to the
Time for the phe-
Standard Time it is
Time, six hours, etc.
AND VICINITY.
a h P
m m °
+0.1 +-1.9 23
<i, 2 +1.8 29
AND VICINITY
—),§ +2.0 31
—).6 +1.7 39
—1.5 +1.4 83
404 Comet Notes
The approximate times for observers within 300 miles of Omaha can be found
by using the constants a and b, given in the table, according to the formula
G.C.T. = Predicted G.C.T. + aAdr + bAg,
AX and A¢ in this case being obtained by using the longitude (96°0) and latitude
(41°3) of Omaha, and subtracting these, respectively, from the longitude and lati-
tude of the place.
For observers within 300 miles of Mount Hamilton, California, the same rule
is followed using the longitude (121°7) and latitude (37°3) of Lick Observatory.
Only disappearances are given.
Creighton University Observatory. Wx. Cretus Dovte, S.J.
COMET NOTES
By G. VAN BIESBROECK.
Periopic CoMet ENCKE was due at perihelion in the beginning of June but it
was then nearly in line with the sun so that it could not be seen. Its predicted
course showed a rapid southerly motion in June which would have made it visible
for southern observers. A telegram under date June 22, sent by C. D. Perrine,
Director of the Cordoba Observatory in Argentina, brought the first information
of the rediscovery. The comet was located there by Bobone on a photographic
plate from which resulted the preliminary position:
1931 June 21.9328 U.T. a = 7" 35m4 5 = +8° 22’ Mag. 9.
This position shows that Crommelin’s ephemeris (p. 351) requires the corrections:
—69* in a and —48’ in 6. A slightly different ephemeris computed by L. Matkie-
wicz of Pulkovo reduces these differences to —56* and —44’. These residuals
show that the comet passed perihelion on 1931 June 2.9 and is therefore about one
day ahead of the computed position in its orbit.
From now on the conditions of visibility improve rapidly for southern ob-
servers but at the same time the brightness decreases so that this return, the
thirty-seventh since this famous object was discovered, will be one of the most
unfavorable possible. The brightness seems to be somewhat below the expected
value which might account for the failure of earlier attempts at recovery last
winter.
The great value of photographic exposures on the sky as a permanent record
has been illustrated by a recent instance: last spring K. Reinmuth of the Heidel-
berg Observatory found a cometary image on a plate exposed there on 1902 March
4. The object had not been noticed at the time the plate was taken; but the reality
of the image was confirmed when Reinmuth recognized the same object on plates
that had been taken the following day, 1902 March 5. It was moving slowly and
appeared as a little spot about 1°5 in diameter with a faintly visible diffuse nucleus.
The magnitude was estimated as 12. A faint appendage in position angle 220°
suggested the presence of a tail. From the positions on the two successive nights
B. Asplind has deduced a circular orbit indicating a large distance and a small
inclination :
Node £2 318° 54°5
Incl. i = 8° 18
Radius of orbit 6.89 astr. units
Arg. of latitude 207° 37:4 on 1902 March 4.5 M.T. Berlin.
Comet Notes 405
A. C. D. Crommelin failed to identify this object with any of the older known
comets, but L. E. Cunningham succeeded in establishing the correct identification.
In Harvard Announcement Card 159 he shows that this image belongs to Comet
1925 II (ScHWASSMANN-WACHMANN) for which
= 322° 44’
i = 9 26'
a = 6.43
according to the elements by Berman and Whipple. Their orbit corresponding to
a period of 16 years represents the 1902 position within a couple of degrees and
the daily motion fits exactly.
—
It will be remembered that this comet has shown very large fluctuations in
brightness (see the illustrations in the April number of this year, p. 224) and that
it seemed certain that, owing to the nearly circular shape of the orbit, this object
might remain visible during its whole period of revolution around the sun. The
1902 observations confirm this expectation since at that time the comet was not far
from aphelion which had come toward the end of 1900, but it seems that the Hei-
delberg observer has caught the object in 1902 during one of its curious outbursts
of light.
Comet 19306 (Beyer) is still under observation: on June 15 it was photo-
graphed by M. Wolf with the Heidelberg reflector and estimated as 16™.5. Further
observations by the writer on July 16 and 17 show it reduced to a hardly notice-
able diffuse coma of magnitude 17 and about 2’ in diameter. It is doubtful whether
further observations will be obtained of this comet which has now been followed
for 21 months.
So far Comet 1913 III (Neuvymin), which, although faint, comes now under
better conditions of visibility for northern observers, has not been recovered. It
may be fainter than was expected or else the position may not be predicted closely
enough. The search is being continued by the writer.
A telegram relayed through the Harvard Observatory in the afternoon of
July 18 has brought the first information about an apparently new comet. The
telegram read:
“Van Maanen telegraphs Nagata’s Comet photographically confirmed by
Moore Mount Wilson July 17.685U.T. Right ascension 10°41", Declination
+9° 48’.”
No indication was added as to the direction of motion nor was the brightness
mentioned. The region is only visible for a short time after sunset and the object
was therefore probably bright. In the evening of July 18 the comet was not found
at the Yerkes Observatory. The sky was transparent but the view from the comet-
seeker was intercepted by the big dome, the field was hidden by trees for the
Bruce telescope so the search was made first with a binocular and next with the
3-inch finder of the 12-inch refractor. The nearby crescent of the moon added
to the difficulty. It is to be hoped that other observers have been more successful.
Williams Bay, Wisconsin, July 19, 1931.
ADDENDUM.
Three additional positions of Nagata’s Comet have been received from Mount
Wilson by telegraph, as follows:
Date R.A. Dec. Authority
1931 oe ni
July 18.1792 10 40 44.7 +9 51 03 Nicholson and Moore
19.1861 10 45 06.0 +9 54 47 Nicholson and Moore
20.1790 10 49 22.3 +9 58 12 Nicholson and Ross
Tail four degrees. Magnitude 9 (Aitken).
406 Meteor Notes
METEOR NOTES
By CHARLES P. OLIVIER.
The writer is on vacation and has left directions at the Flower Observatory
that observations were not to be forwarded to him. Hence the time for writing
the usual Meteor Notes has arrived, and the only observations here are a few
that were enclosed in private letters. These will be briefly mentioned. Through
Mr. R. A. McIntosh, a brief résumé of the recent work of our new member, Mr.
Geddes, of New Zealand has been received. His detailed results will appear later.
He observed 79 meteors on 10 nights in February, 108 on 6 nights in March, 212
on 9 nights in April, and 58 on 4 nights in May. This is an excellent record of
457 meteors in four months. They are particularly valuable as coming from the
Southern Hemisphere.
Through our colleague, Professor M. Dartayet of the La Plata Observatory,
we received the detailed results of the work of Mr. J. L. Munoz of Lomas de
Zamora, Argentina. The tabular results appear here; the radiants will be worked
up later. From the U. S. Weather Bureau come reports of fireballs on May 3, 5,
6, and 12 from ships at sea. All the other observations received at Flower Ob-
servatory during the past month or two will have to await future discussion, as
the writer has not seen them.
The University of Pennsylvania has authorized the securing of the services of
a special assistant for a year to help reduce back observations, largely those of the
A.M.S. This assistant will begin in September, and it is hoped that rapid progress
will be made. Also that it will be more possible to keep up with current reports.
Recently Harvard College Observatory has announced the establishment for
a year of two regularly equipped meteor stations in Arizona, to be manned by
professional astronomers devoting all their time to meteoric research. Professor
C. C. Wylie has for some years carried on very successful researches on fireballs
and meteorites in the Middle West, as has Dr. W. J. Fisher in New Zealand. With
all this increase in interest in meteoric astronomy we do not wish the A.M.S. to
fall behind. But in order that our results shall show up well in comparison, it is
essential that more of our members work harder. Especially they should acquaint
themselves with the nature of the problems that need solution, and try to keep up
at least partly with what others are doing. In other words, study as well as night
work is an essential for a man who hopes to do the most valuable work. It is
quite true that we welcome and need men and women who are good observers
only—our central office will gladly reduce their results. But even for them a
slight knowledge of what they are about and to what their observations may lead
will be most helpful.
Through the daily press, magazine articles, and over the radio much publicity
has been given to meteors of late. This should lead to an increasing number of
people sending in usable observations of fireballs, as well as of the few showers
that the casually interested person might turn his attention to. As such good
results were obtained in places favored with clear skies in both 1928 and 1930 on
the Leonids, there is good hope for increasing showers during the next two to
four Novembers. It would be a great pity for such a shower as that of 1833 or
1866 to appear and be inadequately observed. But proper observing cannot be
done without a little preparation and practice. This is one good reason for the
Meteor Notes 407
campaigns of the last few years in each August and November. In any case, the
more intelligent people become interested in meteoric astronomy, the faster it will
progress.
As to our regular members, those in the same state or adjoining states, par-
ticularly when 100 or less miles apart, are urged to communicate with one another
and undertake simultaneous programs. This is far the best way to stimulate both
accuracy and interest, as reductions show at once the points where improvement
are most needed.
Joaguin L. Munoz, LomAs pe ZAMorA, ARGENTINA.
1931 Began Ended Total Meteors Factor Rate Cor. Rate
Jan. 15 22 :20 24 :00 100 9 0.9 5.4 6.0
18 22:17 24:19 122 16 1.0 7.9 7.9
Feb. 10 21:58 23:25 87 10 1.0 6.9 6.9
11 22:33 23 :50 99 19 1.0 12.3 12.3
12 21:33 23:37 104 26 1.0 15.0 15.0
13 22 :07 22 :56 49 15 0.8 19.5 24.4
The time used in the above is as of 3 hours west and is counted from mid-
night.
The names of several new members will appear in the next Meteor Notes.
Four theoretical papers on meteors have been finished by the staff of Flower
Observatory recently and await publication. Two are independent investigations
of the errors made and the accuracy to be expected in Schaeberle’s Method for
computing heights. The paths of several fireballs are under investigation and
will be finished in the relatively near future.
Chesterbrook Farm, Rosslyn, Virginia, 1931 July 15.
The Fall of a Large Meteorite
On June 10, 1931, press reports carried the account of a mysterious shock,
generally attributed to a meteor, which rocked northern Ohio
The following is from a Michigan daily:
about 2:00 a.m.
A meteor measuring more than ten feet in diameter stru
near here early today with terrific force, shattering windows in nearby
houses and frightening residents from their homes.
Sleepers tumbled from their beds in alarm as the comet struck with
a resounding roar. Buildings in the near vicinity were rocked and window
panes were shattered. The intonation was heard for mil leading
frightened inhabitants to believe an explosion had occurred. The meteor
buried itself twelve feet into the ground, a quarter mile north of town. A
few feet over and it would have crashed into the concrete pavement.
Mr. Stuart H. Perry, of Adrian, Michigan, owner of the smaller Paragould
meteorite, made a personal investigation which definitely showed the incident must
have been caused by a cache of high explosive rather than by a meteor. No
meteor was seen by persons outdoors, and a large meteor should have made a
brilliant light conspicuous at a distance of more than a hundred miles. The
report was a single sharp explosion, without the following roar characteristic of a
meteor. Finally, oil well drillers said the force of the shock indicated about 30
quarts of nitroglycerine might have been used.
Although this was evidently due to high explosive, it is worth while to con-
sider the probable effect of the fall of a meteorite “measuring more than ten feet
in diameter.” The heights of disappearance have been computed for meteors of
various sizes as: for ordinary shooting stars, 55 miles; for fireballs, 35 miles or
lower; where meteorites have been recovered, an average of fourteen miles; for
408 Monthly Report of the American Association
the Paragould meteorite, the largest observed, five miles. This suggests that for
a meteor several times as large as the Paragould, the cap of incandescent gas
giving the fireball appearance would accompany the meteor to the surface of the
earth. Observation and calculation agree that for the ordinary meteorites ob-
served to strike, the velocity of striking is less than the velocity of sound through
air. For large meteorites weighing many tons, the case is different.
For an iron sphere weighing 125 tons and entering the earth’s atmosphere with
a velocity of ten miles per second (near the minimum possible), Professor
Moulton calculated that the striking velocity after a vertical fall would be 3.8
miles per second. At this speed, the kinetic energy is nearly three times the
energy of an equal weight of nitroglycerine. As this tremendous amount of
energy must be converted into heat almost instantly, it appears that much of the
meteorite, and a certain amount of rock and earth would be vaporized with such
suddenness as to cause a violent explosion, more violent than an equal weight of
nitroglycerine.
Professor Moulton applied this result to Meteor Crater, deducing that the
mass was probably much smaller than previous estimates which failed to take
account of the enormous kinetic energy; and also that the main mass was prob-
ably entirely vaporized at the time of striking. He believes it is useless to con-
tinue mining operations in search of the “main body.”
If the meteoric theory is correct, the same reasoning can be applied to the
Siberian incident of June 30, 1908. From a discussion of the air waves as record-
ed in England and other information, Whipple accepts 130 tons as a reasonable
estimate of the weight of the meteor. A single iron sphere seven feet in diameter
would be of about the right order of weight. If, as is possible, his estimate of
velocity is too high, the weight should be correspondingly increased. On this
assumption, the hot gas which spread with explosive force was from the vaporized
meteorites. The air driven out from in front of the meteor was a minor item.
wit ' C..C. Wri.
University of Iowa, July 19, 1931.
VARIABLE STARS
Monthly Report of the American Association of Variable Star
Observers for May and June, 1931
Herewith is the usual double, summer report, representing the work of 44 ob-
servers on 413 variables, totalling 3752 observations. New contributors include
Charles T. Vorhies of Tucson, Arizona, who has been observing under the guid-
ance of Mr. Jos. Meek, C. Mennellay of Naples, Italy, who has been tutored by
Professor A. Bemporad, and Mr. A. B. Aldwell of San Francisco, California. Fr.
McNally, of Georgetown College Observatory, and Sig. Ancarani, of Faenza, Italy,
also return to the ranks of active observers after an interval of several months.
Mr. R. N. Buckstaff, of Oshkosh, Wisconsin, reports that he took unto himself a
mate on J.D. 2426523, and that the Association thereby gains a prospective observer.
The Chart Curator, Mrs. Helen S. Hogg, who has been at Mount Holyoke
College Observatory for the past year substituting for our Miss Farnsworth, will
after August 1 take up her residence in Victoria, B. C., Canada, where Dr. H. S.
Hogg has recently been appointed a member of the staff of the Astrophysical Ob-
VARIABLE STAR OBSERVATIONS RECEIVED Durinc May AND JUNE,
April 0 = J.D. 2426432; May 0 = J.D. 2426462;
J.D.Est.Obs. J.D.Est.Obs.
V Sct
pat 39
406 10.8 Bl
S Sci
001032
410[11.1 Bl
X AND
001046
396[12.9 Rs
474 8.3 Me
485 9.1Fd
T AND
001726
488 13.2 Pt
505[12.3 Gy
Tt Cas
001755
423 87L
438 10.3 Th
439 9.4 Ah
440 9.4 Ah
440 9.0Jo
440 10.2 Th
442 10.4L
443 9.5 Jo
444 10.5 Th
444 9.7 Ah
445 10.8 Pt
446 10.0 Jo
450 10.7 Jo
450
452
454
10.2 Th
10.6 L
10.8 Jo
10.6 Th
R ANpD
“001838
477 11.6 Fd
479 11.2 Gy
48s 11.4 Fd
488 11. 4 ‘* t
505 11.9 Gy
S Tuc
001862
407 [13.2 En
410[12.4 Bl
10.4 Me
of Variable Star Observers
T PHE
002546
9.3 Bl
9.4 En
418 9.5 Bl
442 98 Bl
W Sci
0028 33
410 13.1 Bl
Y Cep
003179
450 10.4 Pc
U Cas
004047
406
407
[
V AND
004435
486 10.2 L
x Sch
004746a
485[12.1 I'd
Cas
004746b
485 10.6 Fd
488 10.5 Pt
W Cas
004958
439 9.5 Ah
440 8.9Jo
440 9.6 Ah
443 9.0Jo
444 95Ah
445 91Pt
446 9.0Jo
450 9.2Jo
452 99 BL
456 9.7 Jo
485 9.7 Fd
488 10.6 Pt
U Tuc
005 175
406 8.7 Bl
407 89 En
411 8&7 Ht
414 83En
415 86 Ht
418 8.5 Bl
421 8.5 Ht
421 86En
436 8&8 Ht
440 8.7 Sl
440 8.7 Dr
442 9.1 Bl
J.D.Est.Obs.
U Tuc
005475
8.9 Sl
8.9 Dr
9.7 Bl
9.2 Ht
8.8 Dr
9.5581
U Sci
010630
410 96Bl
U ANpD
010940
423 128 L
UZ Anpb
011041
423 14.0L
S Cas
011272
474[12.5 Me
RZ
448
450
Ringer
45
45:
455
455
021258
440 8.4Jo
440
8.8 Ah
J.D.Est.Obs.
T Per
021258
443 84Jo
445 8.7 Pt
446 8.5 Jo
449 87 Me
450 8.6 Jo
450 9.0 BL
452 88BL
Z Crp
021281
447{13.1 Pe
o CET
O02T 403
383 9.4Mn
407 8.9 En
438 5.9SI
S PER
021558
440 8.4 Jo
440 9.5 Ah
443 &3To
445 9.6 Pt
446 83Jo
449 9.5 Me
450 94Bg
450 84 Jo
450 10.0 BL
452 9.7 BL
479 9.7 Sz
488 95Pt
RR Pe
022150
423[13.7 L
R For
410 85BIl
442 8.5Bl
451 9.0 Bl
RR Cep
022980
447 13.0 Pc
R Tri
023133
505 7.1 Gy
W PER
024356
436 9.3Ch
440 8&8 Jo
443 88 Jo
445 87 Pt
446 8&7]Jo
449 9.2 Me
450 9.0Jo
450. 9.1 Bg
467 9.5Jo
471 98Jo
474 9.5 Mc
488 8.8 Pt
409
1931.
June 0 = J.D. 2426493.
J.D.Est.Obs.
R Hor
O
408
410
411
415
415
420
421
436
440
440
442
447
450
451
453
467
T
410
41]
415
415
440
450
452
467
25050
10.1 En
9.5 Bl
9.8 Ht
9.5 Ht
9.5 En
8.7 En
9.2 Ht
7.3 Ht
7.0 Dr
6.8 S]
6.9 Bl
6.4 Sl
6.2 Dr
6.4 Bl
6.1 Ht
5.8 Dr
Hor
25751
12.5 Bl
12.9 Ht
12.9 Ht
12 21 P
13.3 Dr
13.1 Ds
Lyte
3 Dr
x Cor
0?
a9
3/0
425
450
450
451
488
R
MOL
10.4L
9.7 Pt
10.5 Jo
10.9 Me
10.6 To
10.5 BL
10.4 Me
90 Pt
PER
0323
423
442
443
445
446
448
454
458
Nov
325355
10.0 L
9.0L
9.3 Jo
8.7 Pt
9.1 Jo
9.0 To
921
9.0 Jo
PER
032443
445|
uy
13.2 Pt
06
CIP
J.D.Est.Obs.
U Eri
034625
408 10.5 En
413 10.6 En
415 10.6 En
420 10.8 En
440 11.8 Dr
T Ert
035124
8.8 En
8.6 En
8.5 En
8.0 En
8.0 Dr
8.9 Dr
W Eri
040725
440 10.2 Dr
10.3 Dr
W Tat
042215
425 10.3 L
440 9.6 To
442 10.1 L
143 95To
445 10.1 Pt
446 93 To
450 94Jo
454 10.1 L
Tr Cam
043065
408
413
415
420
440
467
467
423 144L
441 12.3 Jo
442 142L
445 14.0 Pt
i3./ Pe
447
450 12.0 Jo
454 13.7 L
460[12.2 An
467
471 11.8 Jo
487
12.0 Jo
5a Se
S Ret
043163
440 11.2 Dr
450 11.2 Dr
467 11.2 Dr
RX Tau
043208
443[12.0 L
R Ret
043263
8.7 En
8.4 Bl
8.4 Ht
8.8 En
9.0 Ht
9.6 Ht
408
410
411
413
415
421
410
Monthly Report of the American Association
VARIABLE STAR OBSERVATIONS RECEIVED DuriING MAy AND JUNE, 1931.
J.D.Est.Obs.
R Ret
043263
436 10.4 Ht
437 10.4 En
440 10.1 Dr
440 10.2 Sl
442 98 Bl
449 10.9 En
450 10.5 Dr
451 10.7 Bl
453 11.2 Ht
455 11.0S1
467 11.5 Dr
X CAM
043274
9.5L
442 10.6L
445 11.3 Pt
447 10.7 Pc
454 11.6L
487 12.1L
R Dor
423
S
~
Is
he
nN
%
rar
— bent
Wwe OS
it
Awumwua
450
451
453
455
467 Dr
R CAE
013738
408 11.9 En
410 12.2 Bl
411 12.1 Ht
413 12.0 En
437[12.0 En
440 13.2 Dr
453[12.0 Ht
467 [13.4 Dr
Rm Fic
044349
08 82En
410 86Bl
411 86Ht
413. 8.2En
415 86Ht
421 84Ht
_
=
ro)
ALUWUMNSDUWNIns Urry 14S €
Ube ty Ww Ota BRB NWN UID
ao
J.D.Est.Obs.
R Pic
044349
422 82En
436
437
440
442
449
450
451
453
467
V Tau
044617
9.1 Pt
8.9 Ch
91B
R Ort
045307
425 11.8L
443 12.0L
447 11.8 Ch
R Lep
04551.
380
398
425
440
447
449
456
ININNNNNN
mONNN WO
—
—
cr
=. 1)
As
445
447
449
~S
a
aa
~
—_—
—
TUNANN
RrAMUW
BnrsaS
ss
aN
—_)
2
—
6.2 S]
V Ort
050003
443 13.5L
T Lep
050022
408 8&8En
410 88 Bil
413 91En
422 10.5 En
437 10.4 En
442 10.1 Bl
449 11.2En
451 10.4 Bl
S Pic
050848
9.8 En
8.7 Bl
9.3 Ht
9.6 Ht
9.9 En
9.7 Ht
2 10.0 En
10.3 Ht
10.6 En
9.8 Dr
10.0 Bl
11.1 En
10.4 Dr
10.1 Bl
J.D.Est.Obs.
S Pic
050848
453 10.4 Ht
R Aur
050953
12.8 Pt
13.0 Ch
13.2 Pt
T Pic
051247
10.6 En
10.1 Bl
10.0 Ht
10.0 Ht
9.3 En
9.9 Ht
9.2 En
10.0 Ht
9.4 En
9.6 Dr
10.0 Bl
9.5 En
9.6 Dr
10.1 Bl
445
447
475
410
410
411
415
415
421
422
436
438
440
442
449
450
Jt
>
uv
AS
3
>
p="
G
415 9.7 En
421 10.3 Ht
2 10.0En
438 10.5 En
10.7 Dr
10.8 Bl
10.9 Dr
1 10.9 Bl
453 11.0 Ht
S Aur
052034
9.0 Ch
9.0 Jo
9.0 Jo
8.3 Pt
9.0 Be
437
441
445
445
447
447
447
448
450 9.2Jo
450
450 92BL
451
452
455
465
J.D.Est.Obs.
S Aur
052034
466 88Fd
466 8.6Jo
469 89 Jo
475 8.6L
W Avr
052036
Oz.
8.9L
9.3 Jo
931,
8.9 Pt
9.2 Jo
9.4 Be
9.4An
9.6 Ch
9.3 Jo
96 Sf
9.0 Jo
9.5 Mg
9.3L
95B
9.9 Sf
9.8 Jo
407 98L
9.6 Jo
423
432
441
442
445
445
447
447
447
—)
445
446
446
447
448
450
450
454
S Cam
053068
9.6 Pc
9.2 Jo
9.0 Jo
9.7 BL
9.8 BL
9.0 Jo
10.0 BL
10.1 BL
447
447
450
450
452
453
455
461
S Cam
053068
10.1 BL
10.2 BL
10.3 BL
9.5 Jo
10.0 Pt
9.3 Bg
462
465
468
471
475
479
490 10.7 BL
RR Tau
053326
423 13.0L
425 12.9L
426 13.1L
428 12.7L
431 13.1L
442 113 L
443 12.1L
445 12.6L
446 12.7L
447 12.9L
450 11.6L
454[12.1 L
461 12.5L
.V Aur
053337
447[12.8 Ch
475[12.0I
U Aur
053531
423 771L
431 7.4L
433 7.7 Ah
434 7.7 Ah
435 7.7 Ah
439 7.8Ah
440 7.7 Ah
442 7.6L
444 78Ah
445 80Pt
447 7.5Ch
448 7.9 Ah
450 7.2B
450 7.8Jo
450 8.0Sf
452 7.7Jo
454 79L
456 8.1Ah
465 84Sf
466 85Jo
469 84]Jo
471 83Jo
475 88&L
SU Tau
054319
423 12.0L
425 12.0L
428 12.1L
436 10.8 Ch
442 12.0L
J.D.Est.Obs. J.D.Est.Obs.
SU Tau
054319
445 12.0L
445 11.5B
445 11.7 Pt
447 11.7 Pc
11.6 Ch
11.9L
11.7 L
11.4 Pe
11.4 Ch
11.6 Mg
11.0 Pt
af be
11.8L
2 110 Pe
6 11.6 Pt
y faa i
= (oi.
443 13.3 L
454 13.1L
RU Tau
054615c
423 11.9L
443 12.4L
447 12.5Ch
454 119L
R Cor
054620
407[12.4 En
411[13.0 Bl
415[13.0 Ht
415[13.0 En
421[13.0 Ht
422[12.4 En
438[13.0 En
442[13.0 Bl
449[13.0 En
453[13.0 Ht
a Or!
054907
0.3 SI
0.3 SI
0.2 S1
0.1 Sl
443
447
450
452
of Variable Star Observers
——————— ae
VARIABLE STAR OBSERVATIONS RECEIVED DURING
J.D.Est.Obs.
U Ort
054920a
439 9.7 Ah
441 9.3 Sl
445 9.4Sl
445 10.2 Pt
446 9.9 Jo
447 10.0 Ch
448 10.0 Jo
450 10.2 Jo
450 10.1 Wd
452 10.2 Sl
459 10.4 Wd
465 10.5 Wd
Z AUR
055353
445 10.2 Pt
447 10.2 Pt
449 10.2 Pt
449 9.7 Me
10.2 Pt
9.7 Me
10.3 Pt
9.6 Me
2 10.2 Pt
2 98Pt
6 10.1 Fd
6 10.0 Pt
9.7 Me
3 10.3 Pt
10.2 Mc
10.5 Mec
10.2 Fd
10.2 L.
10.5 Mc
10.4 Mc
479 10.3 L
480 10.2 L
481 10.5L
494 10.2 L
498 10.3 L
561 10.3 L
R Oct
055686
411 12.4 Bl
415[12.0 Ht
pation
rate
490
476
478
7
mw
ww
—_
—
dt
o<
—
=]
SOonhku
Of
ox
ts
- +
NO
—
NNN
YN
_
—
W
J.D.Est.Obs.
X AuR
060450
10.5 Pt
10.7 Sf
10.7 Pe
11.1 Ch
11L.2Sf
454 11.4L
462 11.6B
467 12.1L
445
447
447
451
452
475 13.6 L
V Aur
061647
423 10.2L
442 10.3 L
446 10.1 Ch
450 9.0 Bg
453 9.2Bg
453 99B
454 99L
459 91Be
473 9.7Mec
478 94B
479 86Bg
486 9.1L
V Mon
061702
445 12.4 Pt
AG Aur
062047
425 10.0L
442 92L
454 94L
467 9.4L
486 98L
U Lyn
063159
449 10.6B
R Mon
063308
447 12.6Ch
451 12.5 Ch
Nov Pic
063462
407 8.5En
410 85En
411 83Ht
415 83Ht
421 84Ht
422 85En
427 84En
438 8&5En
449 86En
453 83 Ht
454 84En
S Lyn
063558
425 14.6L
445 13.8 Pt
467 14.1L
J.D.Est.Obs.
S Lyn
063558
475 13.2 Pt
X GEM
064030
449 12.8B
449 12.7 Me
451 12.7 Me
465 13.0 Bw
467 13.0 Me
471 12.8 Me
Y Mon
065111
425 13.1L
437 13.2 Ch
443 13.7 L
445 13.4 Ch
449 13.7B
450 13.6 Be
453 13.6 Bg
X Mon
065208
425 7.2L
440 7.3Dr
443 7.3L
447 78TEf
450 7.5Dr
453 7.9 Tf
454 7.7L
457 84Tf
459 85Tf
R Lyn
065355
425 13.3 L
443 13.2L
449 13.7B
RS Gem
065530
466 11.0 Ma
Z CMA
O650IT
440 10.2 SI
447 10.3 Sl
455 10.4Sl
V CMr
070109
451[12.5 Ws
R Gem
070122a
439 10.2 Ah
441 10.5Jo
445 10.5 Jo
445 10.8 Pt
445 10.0Ch
446 10.6 Jo
449 10.2 Me
450 10.7 Jo
450 10.3 Bg
450 10.3 Wd
453 10.8 Jo
J.D.Est.Obs.
R Gem
070122a
456 10.5 Wd
459 10.6 Wd
459 10.1 Bg
461 10.7 Wd
462 10.7 Wd
462 104B
10.9 Wd
11.0 Jo
10.4 Me
10.9 Wd
10.5 Al
465
466
467
467
468
471
475
479
= A
3 =
Van Pind
DYiZoOoOn YG)
— bh
=“
to
wn
v2
oO 20
[2 02 02 CO GO DO
50 Un ST CO BOND UI
x»
I
8.6 Me
8.4 Ws
8.6 Jo
8.4L
8.3B
8.6 Sf
8.4 Ws
8.4 Jo
8.5 Me
8.2 Jo
R Vou
070772
410 10.4 En
411 10.2 Ht
415 10.0 Ht
415 10.7 En
421 10.1 Ht
422 10.9 En
438 10.9 En
440 99Dr
449 11.3 En
453 10.8 Ht
456 11.6 En
411
May AND JuNE, 1931.
J.D.Est.Obs. J.D.Est.Obs.
L. Pup Z Pup
071044 072820b
440 5.4Dr 38 12.7 En
440 5.2S1 449[12.1 En
448 5.2Sl S Vo.
449 5.8Dr 073173
450 5.6Dr 410 11.8En
456 5.4S1 411 116Ht
467 5.2Dr 411 12.0Bl
RR Mon 415 11.4Ht
071201 415 12.2 En
446 11.0Ch 421 114Ht
447 11.4S£ 422 12.2En
449 10.9Me 438 12.2En
451 10.9Me 440 12.1 Dr
451 10.8GC 442 11.9Bl
452 110GC 449 11.8 En
452 10.6Sf 451 11.8Bl
461 10.0GC 453 11.4Ht
465 98Sf 456 12.2En
467 7 Me U CM
470 9.7 Me 073508
V Gem 425 11.4L
071713 443 12.4L
425 Mts 445 12.1 Pt
443 8.1L 445 12.0 Ch
445 8&3 Pt 449 12.5B
445 83Ch 450 12.5 Bg
449 84Me 454 12.9L
451 85GC 475 12.5 Pt
452 84GC 480 13.3 Bg
454 8.6L S GEM
457 86B 073723
461 9.0GC 446[13.6 Fd
467 9.2Vh 473[13.5 Mg
467 9.2 Me W Pup
474 96Vh 174241
475 9.0Pt 410 8.2En
477 97B 411 88Ht
S CM 411 8.5 Bl
072708 415 8.0Ht
437 119Ch 417 8.6 En
438 11.9Ke 421 8.7 Ht
443 120Ke 422 87En
445 118Pt 428 9.0Ht
447 11.7Pc 438 9.4En
449 11.5Ke 440 9.5Dr
466 10.6Fd 449 10.3 En
470 11.2B 452 10.5 Bl
475 10.3 Fd
475 11.0 Pt
T CM1
072811
445[13.2 Ch
473 12.0 Mg
Z Pup
072820b
410 12.0 En
415 12.4En
422 12.4 En
453 10.6 Ht
456 10.7 En
T Gem
074323
438 13.7 Ke
446[13.1 Pc
446 13.51} +y
412
Monthly Report of the American Association
VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND JuNE, 1931.
J.D.Est.Obs.
T Gem
074323
473 13.1Mg
480[13.1 Bw
489[13.1 Bw
U Pup
075612
447 11.4Ch
R Cnc
081112
433 8.2 Ah
434 8.2Ah
435 8.1 Ah
438 7.8Ch
439
440 7
441 7.
443 7.
444 7
445 7.11]
446 69Jo
447 6.9 Pc
448 7.3 Ah
450
451 6.9Ws
452 7.0Ch
452 69Wd
453 6.6 Jo
456 6.9 Ah
457 69B
459 6.9Wd
462 7.0Wd
464 7.1 Ah
465 6.7 Ws
465 7.0Wd
467 7.0Wd
473 7.4Mc
475 7.0 Pt
478 7.0B
480 7.0 Wd
489 7.2Wd
V Cnc
081617
425 9.7L
434 10.8 Ah
438 10.6 Ke
439 10.8 Ah
443 11.8 Ch
443 10.4 Ke
443 11.4L
445 11.6 Pt
446 11.2 Gy
449 11.5 Me
449 11.6 Ke
451 11.2 Gy
465 12.0 Wd
470 120B
472 123L
475 12.4Pt
487 12.4B
J.D.Est.Obs.
RT Hya
082405
438 84Th
439 81Ke
440 84Th
442 7.5Mp
444 82Th
444 8.1Ke
445 78Pt
447 9.0Jo
448 8.0Th
449 7.9 Ke
449 7.8Me
451 7.7 Me
452 79Th
453 7.5 Bg
457 8.0Th
466 7.6 Me
466 7.8Th
472 7.8Th
474 7.3 Mp
475 7.6 Pt
R CHa
082476
410 12.8 En
411 12.5 Ht
411 12.5 Bl
415 12.5 Ht
421 12.6 Ht
438[12.4 En
440 13.3 SI
442[12.6 Bl
449/12.4 En
453[12.6 Ht
U Cnc
083019
44. 3 14.3 L
495/12.9 Bw
X UMA
083350
439 13.5 Ke
444 13.3 Ke
449 12.5 Ke
449 128 Me
450 12.8 Be
451 12.5 Me
467 10.7 Me
470 10.5B
470 10.5 Me
471 10.8 Jo
472 10.0 Vh
475 10.1 Pt
478 10.3B
479 10.3 Bg
9.5 Jo
9.4]Jo
J.D.Est.Obs.
S Hya
084803
443 11.4Ch
445 11.4 Pt
447 11.5Jo
450 10.8 Bg
451 11.0Jo
459 10.3 Bg
467 9.6Jo
467 9.5B
467 9.6 Jo
467 9.6 Me
471 9.4Jo
475 86Fd
475 8.9 Pt
477 9.0B
T Hya
085008
425 9.0L
443 9.9L
443 10.1 Ch
444 10.5 Jo
445 10.2 Pt
448 10.5 Jo
452 11.0 Jo
469 11.2 Mg
472 11.4L
478 11.8B
T Cne
085120
441 89Jo
443 88 Jo
443 9.4Ch
445 9.0 Pt
446 88Jo
9.8 BL
450 8&7 Jo
1 9.1 Me
2 99 BL
3 8.6 Jo
5 9.6 BL
461 O8BL
2 99 BL
465 9.7 BL
9.8 BL
475 84Pt
476 96 BL
478 95 BL
9.3 BL
a Vx
090031
411 [u Bl
442 [t Bl
V UMaA
090151
426 10.8 L
439 10.6 Ke
442 10.6L
444 10.2 Ke
449 10.8 Ke
J.D.Est.Obs.
V UMA
090151
450 10.4 Sf
465 10.4 Sf
470 10.3 B
471 10.2 L
473 10.7 Mc
474 10.6 Mc
476 10.8 Mc
476 10.3 Sf
478 10.8 Mc
485 10.1B
487 10.2 L
495 10.0Sf
506 9.9 Sf
U Cnc
090425
426 14.1
439
443
443
443
444
449
450
467
472
477
483[12. Mp
494 12.4 Al
RX UMa
090567
426 10.8 L
442 99L
471 10.4L
487 10.8 L
RW Car
091868
410 12.8 En
411 12.6 Ht
411 8 Bl
415 It
416 ‘n
421 It
422 ‘n
427 n
437 n
442 31
443 10.9 Dr
450 10.7 En
451 10.6 Bl
453 10.4 Ht
456 11.0 En
Y VEL
092551
411 13.5 Bl
415[12.9 Ht
421[12.9 Ht
422[12.4 En
437[12.4 En
ARO
> Oo oO
Dio Who?
he)
bet et at bd
GCOnm
ww UA
ht — bo
bo II WW WWW WHYS:
NS
WL
= SRN NNN
Zt
8 E
At
a8:
OF
8E
OT
9
J.D.Est.Obs.
Y VEL
092551
442 13.2 Bl
448 14.6 Dr
448 14.5 Dw
450[12.9 En
451 13.4 Bl
456[12.9 En
R Car
092062
410 99En
411 9.7 Ht
411 99BI
415 98Ht
417 99En
421 9.9 Ht
422 9.7 En
9.7 En
9.5 Dr
9.7 Si
442 10.0 Bl
448 9.3 SI
450 9.7 En
9.8 BI
10.0 Ht
9.4 Dr
9.2 Sl
9.7 En
X Hya
003014
440 10.3 Jo
443 11.0 Ch
444 10.4 Jo
445 11.1 Pt
446 11.3 Gy
446 10.5 Jo
451 11.3
awe
ALL ADL
wmyuvinnvt
~ >
093934
434 10.9 Ah
439 10.7 Ah
439 10.8 Ke
440 10.8 Ah
441 10.4Jo
443 10.7 Ch
443 10.7 Ke
444 10.6 Ah
445 10.8 Pt
446 10.2 Jo
446 10.1 Gy
447 10.4 Fd
449 9.6 Me
450 9.7Jo
J.D.Est.Obs.
R LM
093934
450 9.9 Ke
453 9.6Jo
466 9.5 Fd
467 86Me
468 8.5Al
469 82Jo
471 8&.1Jo
473 9.1 Ah
475 84Pt
475 81Fd
479 8.0Sz
479 8.6 Gy
494 7.7 Al
495 7.5Jo
498 7.8 Gy
RR Hya
094023
413[12.8 En
438 12.8 En
440 12.7 Dr
450 12.0 En
R Leo
094211
433 63 Ah
434 5
435 5.8Ah
437 5.5 Be
439 5.4Ah
440 5.7 Ah
441 6.2An
441 6.1Be
441 6.2Jo
443 5.5Ch
443 5.3 Tf
444 5.6 Ah
445 58 Pt
445 58Jo
446 5.4Pc
446 5.4Fd
447 5.8Jo
448 5.5 Ah
449 5.7 Me
450 6.0Sf
450 5.7 BL
450 5.6Wd
450 5.7Jo
450 5.5 Me
451 5.5Ma
451 56Al
451 54Bge
452 5.7 BL
452 5.6Wd
453 5.4Tf
453 5.7Jo
455 5.6BL
456 5.4Ah
456 5.6 Wd
457 5.4Tf
_ a - a ee i. oe i, oe
of Variable Star Observers
VARIABLE STAR OBSERVATIONS RECEIVED DuRING MAY
J.D.Est.Obs.
R Leo
094211
459 5.4Tf
459 5.5 Wd
459 5.3 Bg
461 5.7 Ma
461 5.6BL
461 5.7 Wd
462 5.7 BL
463 5.6 Ah
464 5.6 Ah
465 6.0SE£
465 56BL
465 5.7 Wd
466 59Ma
496 5.5 Fd
406 5.8 Me
466 5.9Jo
467 5.8 Wd
468 58BL
468 6.1Vh
469 5.8 Oy
469 6.0 Jo
471 5.8 Wd
471 6.0Me
72 62Vh
473 6.2 Ah
474 6.2 Be
475 6.0 Pt
475 6.1 Oy
475 6.3 Fd
476 5.9 BL
476 6.4 Sf
477 6.0Oy
477 5.8 Wd
478 60BL
479 6.0 Be
479 60Sz
480 6.0 Be
480 6.2 Wd
482 6.6 Fd
484 6.2 Be
484 6.2Jo
186 6.0 Be
487 6.40Oy
487 6.1 Be
488 6.4Jo
488 6.5 Wd
490 6.5 Wd
490 63 BL
490 64B
494 6.2 Al
495 6.4Jo
495 6.5 BL
495 6.7 Wd
495 6.7Sf
499 65 Bg
502 6.6BL
506 6.8Sf
J.D.Est.Obs.
1 Car
094262
440 41 Dr
Y Hya
0904622
413 8.2En
422 81En
438 7.0En
473 6.5 Pt
480 6.6Pt
Z VEI
094953
410 12.2 En
411 12.6 Ht
411 12.3 Bl
415 12.8 Ht
417 12.6 En
421 12.9Ht
422 12.6 En
440 13.1 Dr
448 128 Dr
448 13.2 Dw
451 13.2 Bl
453 13.1 SI
V Leo
095421
440 13.6 Ke
444 13.7 Ke
448 13.7 GC
450 13.7 Ke
451 13.4GC
452 13.5GC
453 13.7GC
467 13.6B
477 13.3B
RR Car
005458
410 7.7 En
411 7.9Ht
415 79Ht
417 7.7 En
421 7.9Ht
423 74En
438 7.6En
$2 79En
453 7.6 Ht
RV Car
005563
411[13.1 BI
. 6 En
443 11.4Dr
451 11.2 Bl
452 11.4En
453 11.7 Ht
454 11.4Dr
J.D.Est.Obs.
S Car
100661
410 58En
411 5.5 Ht
411 5.5 Bl
415 <=
417 5.8E:
421 3s Ht
422 58 “ys
439 6.1 Er
440 37 Dr
440 5.9 SI
450 6.1SI
451 65Bl
452 66En
453 66Ht
454 67Dr
456 6.6S1
467 7.9Dr
U UMa
100860
445 7.1Ch
Z CAR
101058a
410 12.6 En
411 12.4 Ht
411 12.4Bl
415 12.6 Ht
417[12.6 En
423[12.6 En
441 13.5 Dr
448 14.1 Dr
448 13.6 Dw
452[12.6 En
453[12.6 Ht
454 14.2 Dw
454 14.0Dr
* CAR
TOTO58b
441[13.6 Dr
448 13.6 Dr
448 13.7 Dw
454 14.1 Dw
454 13.8 Dr
W VEL
TOTT5?
12.0 En
12.0 Ht
11.7 Bl
411
411
411
415
417
421
423 11.8 En
439
441 93
451 S9OPRI
452 8.7En
453 88 Ht
454 86Dr
J.D.Est.Obs.
U Hya
103212
445 5.6Ch
469 6.1Mc
473 6.2Mc
474 63™Me
476 5.7 Mc
482 5.1Be
RZ Car
103270
411[13.6 Ht
415/13.6 Ht
03769
449 120Be
450 12.7 Pc
456[12.6 Wd
465 13.0 Wd
471 12.0 Jo
473 12.6 Pt
475 12.4B
480 12.4 Pt
494 11.9 Al
495 OWd
496 oo
498
V Hy. \
104620
12.
11.
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ns
411
te
Le)
ax)
PNINININNN
be
2)
2)
r 2)
INIA NININNNININI9O 9
6.6 Pt
RS Hya
104628
411 10.8 En
J.D.Est.Obs.
RS Hya
104628
411 10.5 Bl
416 10.8 En
423 11.1 En
439 11.7 En
451 11.9 Bl
452 12.0 En
W Leo
104814
467[13.8B
477{13.8B
RS Car
TIO261
456[12.3 SI
S Leo
110506
438 13.6 Ke
443 13.3 Ke
443 13.9L
448[13.5GC
450 13.5 Ke
490 11.6 Pt
483 11.9 Mp
RY CAR
AND JUNE,
413
1931.
J.D.Est.Obs.
X CEN
114441
411[13.1 Ht
415[13.1 Ht
417[13.1 En
421[13.1 Ht
439 13.1 En
441 13.5 Dr
452 13.5 Bl
452 12.9 En
454 13.3 Dr
AD CEN
1174858
411 92En
411 9.1Ht
415 93 Ht
417 9.2En
421 94Ht
439 9.2En
441 85Dr
452 91En
453 94Ht
454 8.7 Dr
*W CEN
115058
411 11.4En
411 11.7 Ht
411 11.0 Bl
415 11.0 Ht
417 10.6 En
421 99 Ht
423 9.7 En
427 93 En
439 91En
441 83Dr
451 8&3Bl
452 86En
453 8.3 Ht
454 80Dr
R Cr M
115919
441 82]Jo
443 8.0To
446 79 To
450 82BL
451 &8Ch
451 7.7 Jo
451 83 Ws
452 85 BL
455 87BL
461 91BL
462 89 BL
465 90BL
465 88 Ws
467 9.0 Jo
471 94]Jo
473 98 Pt
476 94BL
478 9.46 BL
480 9.6 Pt
414
Monthly Report of the American Association
VARIABLE STAR OBSERVATIONS RECEIVED Dur1ING MAy AND JuNE, 1931.
J.D.Est.Obs.
R Hya
J.D.Est.Obs.
R Com
115919
490 9.7B
490 9.9 BL
495 10.2 BL
498 10.3 BL
502 10.5 BL
SU Vir
120012
442 119L
445 12.1B
448 11.9 Mp
451 11.6 Ch
451 11.5 Ma
465 11.1 Bw
471 11.6L
473 11.5 Pt
474 11.5 Mp
475 114Me¢
476 11.4Ma
480 11.4 Bw
480 11.4 Pt
483 11.5 Mp
489 11.3 Bw
496 12.0 Bw
510 12.2 Bw
T Vir
120905
425 12.1L
440 13.0 Ke
445 128B
445 12.8L
449 13.5 Ke
472 13.1L
475[13.2 Mg
R Crv
121418
17 L
12.9 SI
12.0L
13.2 S1
13.4 SI
426
440
443
447
456
467
472
122001
ee
8.8 Ke
J.D.Est.Obs.
SS Vir
I2200I
471 8.0Jo
471 8.1Md
472 7.6L
480 7.3Bg
484 8.0Md
493 7.6Md
T CVn
122532
438 10.0 Th
438 9.9 Ke
440 10.0 Th
444 98Ke
447 10.5 Pec
447 10.3 Fd
448 10.0 Th
449 9.7 Ke
451 10.0 Ch
452 10.0 Th
466 10.0 Th
472 98 Th
473 10.0 Pt
477 10.3 Fd
478 98Th
480 98 Pt
483 9.8 Th
484 9.6 Th
495 98Fd
Y Vir
122803
426 11.7 L
445 13.1L
472 14.1L
475[13.6 Mg
U Cen
TUN Ww
RrRhHKLS He
muiummyiwily lor
r
——
+
ie)
So
wwe SYevevvyvy>
J.D.Est.Obs.
T UMA
123160
9.8 Pc
9.5Jo
10.0 Fd
9.8 Jo
10.0 Wd
10.7 GC
10.2 Jo
11.0 Ah
10.4 Wd
10.9 Wd
10.7 Al
11.9 Pt
11.5 Fd
477 12.5 Bc
480 11.8 Pt
485[11.7 Fd
495 11.8 Wd
R Vir
123307
8.0 Ah
8.1 Ah
446
447
449
450
450
452
456
456
459
465
468
473
477
434
435
439
440 84Ah
443
444
448
449
450
451
451
455
456
465
466
9.9 Me
10.0 Ah
10.2 Ws
10.1 Me
466 10.9 Ma
470 10.6 Me
473 10.8 Pt
480 11.0 Pt
338 8.
434 11.8 Ah
439 12.0 Ah
440 12.0 Ah
440
443 1
446
446
447
450
452 1
NNN
GNNWdM
J.D.Est.Obs.
S UMA
123961
456 12.3 Jo
458 11.7 An
465 10.4Wd
468 10.2 Al
471 11.0Jo
473 10.4 Pt
477 10.3 Fd
477 98Bc
480 10.4 Pt
485
488
489 9
490 9.
490 10
495 9
504 9.2 Wd
RU Vir
124204
99L
10.4 Ke
Ee
10.0 B
10.4 GC
10.2 GC
10.3 Bw
9.9L
10.0 Pt
475 10.4 Mg
480 10.1 Pt
480 10.5 Bw
487 10.5L
495 10.6 Bw
510 10.7 Bw
U Vir
124606
427 11.4L
442 12.0L
451 12.0 Ch
472 11.5L
473 11.8 Pt
480 11.9 Pt
482 11.3 Mg
RV Vir
130212
426 13.8L
446 14.0L
451[14.1 GC
451[12.5 Ch
466[13.1 Bw
i
480 12.7 Bw
495 12.2 Bw
510 12.1 Bw
U Oct
131283
8.5 En
427
440
442
445
451
453
466
471
473
411
J.D.Est.Obs.
U Oct
411 8.1Ht
411
415
421 80En
421
439 8.
441 84Dr
451 83 Bl
453 8.7
453 8.6Ht
454 8.6
\
1
449 7
462 7.
466 7
475 7
132002
440 9.4Ke
449 9.7 Ke
480 10.6 Bg
482 10.4Mg
V Vir
132202
444 11.2 Ah
447 10.6 Jo
449 10.2 Ke
450 10.4Jo
10.2 Ch
453 10.2 Jo
456 10.0 Ah
461 93Bg
468
469
471 9.
473 9
480 9
482 9
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411
414
415
418
420
421
425
427
428
438
439
440
445
445
447
451
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of Variable Star Observers
VARIABLE STAR OBSERVATIONS RECEIVED DuRING MAy AND JuNE, 1931.
J.D.Est.Obs.
T UM1
133273
461 9.3 BL
462 94BL
465 9.5 BL
466 9.6 Th
471 98L
472 9.6Th
475 9.7 Th
476 98BL
478 10.0 Th
478 10.0BL
483 10.4 Th
484 10.4 Th
487 10.4L
490 10.5 BL
495 10.7 BL
498 10.9 BL
502 11.2 BL
T CEN
133633
411 65En
411 6.2Ht
411 6.3 Bl
415 65Ht
421 65Ht
423 6.4En
427 63 En
428 6.7 Ht
439 7.0En
440 68S]I1
443. 7.2 Dr
447 73S]
449 8.0Me
451 82Me
451 78Bl
453 7.8En
453 84Ht
454 8.0Dr
456 7.9SI1
466 8.1 Me
RT Cen
134236
411 11.0 En
411 10.9 Ht
411 11.0 BI
415 10.9 Ht
420 11.0 En
421 10.7 Ht
428 10.9 Ht
443 9.9 Dr
451 9.7 Bl
453 10.0 En
453 9.6 Ht
454 95Dr
R CVn
134440
433 7.8 Ah
434 7.9 Ah
435 7.9 Ah
J.D.Est.Obs.
R CVn
134440
439 8.1 Ah
440 8.0Ah
440 7.8Jo
444 8.0Jo
444 8.1 Ah
446 8.1Ch
447 7.7Jo
448 83 Ah
449 8.0Fd
450 7.9Jo
450 7.9 BL
451 82Ws
452 79 BL
455 8.2BL
456 84Ah
461 85 BL
462 87 BL
464 87 Ah
465 87BL
465 84Ws
473 88Pt
475 8.9 Ah
476 9.2BL
477 88Fd
478 94BL
479 9.0 Gy
480 9.0Pt
482 92Me¢
483 93B
490 96 BL
495 98BL
498 99BL
502 9.7 BL
905 10.2 Gy
RX CEn
134536
411 12.4En
411 12.9 Ht
411 12.8 BI
415 13.1 Ht
420 13.1 En
421 13.2 Ht
428[13.1 Ht
443 13.4Dr
453[13.1 Ht
454 13.6 Dr
T Arps
134677
411 13.4 Ht
411 12.9BI
415 13.2 Ht
421 13.0 Ht
423 13.0 En
443 10.5 Dr
451 10.1 BI
453 9.2 En
453 98Ht
454 9.7 Dr
J.D.Est.Obs.
RR Vir
135908
451 12.5 Me
473 13.8 Pt
473 13.8B
475[12.5 Fd
482[14.1 Mg
483[12.8 Mp
Z Boo
140113
425 11.5L
442 10.3 L
444 10.2 Ch
451 10.0 Ma
457 10.1B
471 9.9L
487 10.3 L
487 10.6B
Z Vir
140512
426 14.3L
444[15.2 Ch
446[13.8L
RU Hya
140528
411[13.5 Ht
421[13.5 Ht
428[13.5 Ht
450 14.0 Dr
450 14.1 Dw
452[13.5 BI
R Cen
I40959
407 5.9En
411 59En
411 6.1 Ht
411 6.1BI
414 59En
415 6.1Ht
420 6.0 En
421 5.9Ht
423 6.0En
440 60Dr
440 58S]
443 61Dr
452 62Bl
453 58En
453 6.2Ht
454 63Dr
456 5.9S]
U UMr
141567
434 9.3 Ah
439 92Ah
440 88Jo
440 9.1 Ah
444 92Ah
447 86Jo
447 90Pc
448 8.9 Ah
J.D.Est.Obs.
U UMr1
141567
450 85Jo
453 8.5Jo
456 88Ah
467 78Jo
471 8.0Jo
473 8.1 Pt
473 8.4Ah
475 83 Ah
480 8.0 Pt
483 7.8B
489 80Sz
499 83 Bg
S Boo
141954
426 13.2L
442 13.4L
444 13.3 Ch
458 12.9 An
466[10.6 Th
470 11.9B
471 12.0 Pt
471 12.3 L
478 10.8 Th
480 11.7 Pt
483 10.6 Th
484 10.7 Th
484
484
487
498
142539a
434 O8Ah
439 95 Ah
440 95Ah
440 9.3]Jo
444 92
444 93
446 88
446 93
447
448
449
450
450
450
45
45
45:
45:
456
Renew
oe)
-i
_"
J.D.Est.Obs.
V Boo
142539a
457 84Ah
457 87B
458 84An
460 85 Me
464 8.2 Ah
466 8.2 Me
466 9.0Fd
466 84Jo
467 8.2Vh
458 8.2 Vh
469 8.0Jo
469 86Mc
471 8.0 Pt
472 8.0 Vh
473 8.5 Mc
473 8.0 Ah
47 4 8 2 Mec
475 8.1 Ah
475 85Fd
476 8.0 Mc
476 8.2S8f
477 8.0B
480 8.1 Pt
488 7.7 Jo
495 7.9Sf
496 7.6Jo
R Cam
142584
439 93 Ke
443 8.9 Ke
449 8&7Ke
449 92GD
452 89Ch
183 8.0B
484 8.3 B;
485 83 Th
187 83 Th
R Boo
143227
433 7.9 Ah
434 78Al
435 9 Ah
439 7.9 Ah
440 7.9 Ah
440 78Jo
444 8 0Jo
444 80Ah
446 80Ch
446 7.8]Jo
448 81Ah
450 7.8To
450 8.1 Me
453 8.0Jo
455 8.2 Me
456 84Ah
45
J.D.Est.Obs.
R Boo
143227
8.4 Wd
8.7 Ah
8.5 Wd
8.7 Me
8.8 Jo
8.6 Wd
9.5 Wr
8.8 Jo
9.1 Pt
9.4 Ah
9.5 Ah
9.6 B
9.5 Pt
10.1 Mg
10.2 Sz
10.2 Wd
V Lis
143417
115 LL
10.4 L
10.4 Me
461
464
465
466
466
467
470
471
471
473
475 5
477
480
485
489
489
426
442
449
467
470
471
479 1
480 1 B.
144646a
413 10.2 En
423 10.4 En
451 12.3 Sl
453 11.8 En
U Boo
144918
12.2 Ke
12.0 Ke
439
444
444
449 12
461
465
4 18)
475
443 14.2 Dr
450 14.1 Dw
416
Monthly Report of the American Association
VARIABLE STAR OBSERVATIONS RECEIVED DuRING MAy AND JUNE, 1931.
J.D.Est.Obs. J.D.Est.Obs.
V Aps
145471
443 9.5 Dr
S Aps
145071
1 10.1 En
411 10.0Ht
411 10.0 Bl
414 10.1 En
415 10.1 Ht
421 10.0 Ht
423 10.1 En
440 9.9 Dr
443 98Dr
443 10.2 SI
452 10.1 BI
453 10.0 Ht
453 10.1 En
454 98Dr
456 10.1 SI
456 10.1 En
RT Lin
150018
449 11.9 Me
455 12.2 Me
466 12.5 Me
471 13.1 Pt
480 13.5 Pt
485 13.5 Mg
T Lis
150519
444 13.0Ch
487 13.1B
Y Lin
150605
4% 11.3 L
442 12.2L
449 129 Me
450 12.8 Ke
465[11.3 Ws
471 13.2L
478 13.2B
NWN
wa
on)
NWwWARRRUWCAANNY
i
ZOrHS
=
en >
461
467
pa’
oO
[0 90 90 90 90 90 90 90 90 0 10
Ce
eg eer
487
S SER
151714
426 13.3 L
446 13.3 L
446 13.6 Pc
450 13.4Ke
466[12.6 Md
470 13.3B
471 13.4L
?
:s
NI
ore)
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we
485
487
Ig
Jonna
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YY
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un
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415 10.6 Ht
421 10.0 Ht
428 99 Ht
429 O8L
446 S88&L
449 84Me
453 86Ht
453 83En
467 8.0Me
471 7.9L
479 8.0RB
484 8.1Be
487 7.9L
RU Lir
152714
429 10.8 L
444 11.8Ch
446 1
475 1;
478 1
414
415
418
421
424
428
443
453
453
455 9.8Dr
153215
444[13.0 Ch
J.D.Est.Obs.
S UM1
441
444
444
447
447
450
450
452
456
465
466
467
471
473
476
480
485
495
498
506
R
154428
423
425
426
429
434
435
439
440
440
440
442
442
443
443
444
444
444
444
445
445
446
446
446
153378
10.4 Jo
10.0 Jo
10.4 Ch
10.0 Sf
9.9 Jo
9.7 Jo
9.4 Me
9.8 Sf
9.5 Jo
9.5 Sf
8.9 Me
9.5 Jo
9.3 Jo
8.8 Pt
9.4 Sf
8.6 Pt
88 B
9.3 Sf
8.7 Gy
9.3 Sf
8.8 Dr
10.0 Ht
9.7 En
9.8 Dr
CrB
6.0L
6.0L
6.0L
6.0L
6.1 Ah
6.1 Ah
6.2 Ah
6.3 Ah
6.5 Ke
6.0 Jo
6.0 Be
6.0L
6.0 Jo
6.0L
6.1 Ch
6.3 Ke
6.0 Jo
J.D.Est.Obs.
R CrB
446
447
447
447
448
448
448
448
449
449
449
449
450
450
450
450
450
450
450
450
154428
6.0 Gy
6.1 Ch
6.1 Pe
6.2 Pt
6.0 Jo
6.4 Gh
6.0 Ah
6.0L
6.0GD
6.2 Ke
6.0 Me
6.1 Pt
6.0 Be
6.1 Wd
6.0 Ke
6.0 Jo
6.2 Pc
6.0 Me
6.0L
6.1 Pt
6.2 Pt
6.0 Me
6.1 Wd
6.0 Jo
5.8 Tf
6.0 Jo
50k
6.0 Me
6.1 Ch
6.1 Wd
6.1 Ah
By at
6.0 An
6.0 Be
6.1 Pt
6.2 Pt
6.1 Wd
6.0 Me
6.0 Wd
6.0L
6.2 GD
6.1 Pt
6.2 Pc
6.1 Wd
6.0 Be
6.2 Pc
6.0 Pt
6.0 Jo
6.1 Wd
6.2 Pc
6.1 Pt
6.0L
6.0 Mg
6.0 Mg
6.0 Mc
5.7 Oy
6.0 Jo
6.1 Mg
J.D.Est.Obs,.
R CrB
471
471
471
471
472
472
473
473
473
473
154428
6.0 Mg
6.1 Wd
5.8 Gy
6.0 Sz
6.1 Pt
6.1 Pt
6.1 Pt
6.0 Mg
6.1 Fd
6.0 Be
6.0 Mg
6.0 Jo
6.0 Mg
J.D.Est.Obs.
R CrB
154428
501 6.1 Pt
503 6.1 Pt
504 6.2Wd
504 6.0 Gy
X CrB
154536
429 13.0 L
446 13.2L
473 13.5B
475 13.2 L
R Ser
154615
438 10.4 Ch
446 10.8 Fd
446 11.0 Pc
452 11.1 Ch
461 11.4 Wd
465 11.3 Wd
11.0 Md
10.9 BL
10.5 BL
10.9 Md
11.3 Bw
10.5 B
10.8 Md
9.9 Pt
10.5 BL
10.4B
9.9 Pt
10.3 Md
10.7 Mg
10.6 Th
10.3 BL
10.3 Md
10.2 Bw
10.2 Md
10.5 BL
10.5 BL
R Lis
154715
444 11.7 Ch
479 13.7B
R Lup
154736
443 10.4Dr
454 10.0S1
454 10.0 En
455 10.0 Dr
498
498
502
~ a i ee i oe oe
—— -——
of Variable Star Observers
VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy ANpD JUNE, 1931.
J.D.Est.Obs.
RR Lis
155018
429 14.0L
~)
ft
1552
426 12.1L
444 10.0 Ch
446 10.0L
466 10.3 Md
471 10.4Md
475 10.0 L
484 10.8 Md
485 10.4B
491 10.6 L
493 10.6 Md
497 11.3 Md
RZ Sco
155823
9.5 Ht
9.2 Ht
9.1 Ht
9.2 Ht
9.1 En
9.8 Pt
10.0 Pt
Z Sco
160021
415[12.2 Ht
426 12.2L
415
421
428
453
454
473
480
499[14.1 Be
U Serr
160210
449 11.6 Fd
469 11.6 Me
473 12.2 Pt
480 12.4 Pt
X Sco
160221a
13.5 L,
475 128L
487 12.3 L
SX Her
160325
8.0L
445
423
445
445
447
449
450
J.D.Est.Obs.
SX Her
160325
459 8.1 Pt
461 8.1L
462 8.0 Pt
466 8.3 Pt
467 82Pt
471 82Prt
472 8.2Pt
473 8.1Pt
475 83 Pt
476 8.6L
479 8.2 Pt
480 82Pt
481 8.1 Pt
485 8.1Pt
487 8.0 Pt
487 8.2L
488 8.0Pt
489 8.0 Pt
490 8.0Pt
493 8.0 Pt
494 81Pt
498 8.0 Pt
501 8.0 Pt
503 8.0 Pt
RU Her
160625
422 80L
433 8.1 Ah
435 8.1Ah
438 7.8Ch
439 8.1 Ah
440 81Ah
444. 80Ah
445 7.7L
448 8.0 Ah
452 80Wd
456 8.1 Ah
461 8.1L
466 86Fd
473 83 Pt
475 8&8Fd
475 86Ah
476 8.7L
480 8.5 Pt
485 88B
487 8&7L
490 9.2BL
493 93Me
495 83Wd
498 94BL
502 9.4BL
R Sco
161122a
415[12.6 Ht
428[12.6 Ht
454[12.6 En
473 12.8 Pt
J.D.Est.Obs.
S Sco
161122b
415[12.6 Ht
428[12.6 Ht
454[12.6 En
480 12.5 Pt
W CrB
161138
473 12.2 Pt
480 12.0 Pt
495 11.1 Md
W Opu
161607
429 9.9L
446 9.7L
455 10.4Me
466 10.8 Fd
473 11.2 Pt
474 11.4 Vh
475 11.0L
480 11.3 Pt
V Op
162112
9.1L
10.1 L
9.9 Pt
10.7 L
9.8 Pt
U Her
162119
9.9 Ah
10.2 Ah
10.0 Jo
10.0 Jo
9.9 Ch
10.1 Jo
10.6 Fd
10.2 Jo
10.3 Jo
10.3 Fd
10.8 Jo
10.9 Jo
11.2 Jo
11.0 Pt
10.3 Fd
11.1 Gy
Pt
Fc
429
446
473
475
480
434
439
441
443
444
446
447
450
453
466
466
469
471
473
475
479
480 1
482 1
484 1
485 1 Fd
485 11.1B
496[12.0 Jo
SS Her
162807
422 9.3L
445 10.3 L
461
1
1 1
)
Jo
me oINTty
1.
1:
1.
J.D.Est.Obs.
SS Her
162807
487 11.8L
487 119B
499 99Bg
T Oru
162815
O21,
9.3L
10.4 Pt
9.9L
10.3 Pt
11.4 Bw
11.4 Bw
S Opn
162816
429 13.4L
429
446
473
475
480
507
510
441
444
446
450
450
456
456
469
471
474
476
489
9.3 Jo
9.3 Jo
9.2 Jo
9.2 Jo
10.0 Mc
90 To
9.3 Jo
90To
8.9 To
10.0 Me
10.0 Me
8.9 Jo
R Dra
163266
441 11.8]Jo
443 12.0 Jo
444 12.0 Ch
449 12.1 Fd
450 12.0 Wd
465 4
466
471
475
480
480
482
488
489
495
495
498
—
oO
-
a oO m a
+ * &
a” op
pe beh feed fe ehh
eyerqeryearsard <r"
NMNWUNAONS
et ed ct et ed ey
dq FY TJ 9 |
10.8 Wd
10.8 Wd
11.0 Jo
10.8 Gy
RR Oru
164319
426 13.8L
J.D.Est.Obs.
RR Opu
164319
446 13.8 L
473 11.5 Pt
475 11.3L
480 11.2 Pt
487 10.1 L
S Her
164715
435 9.2 Ah
439 9.2 Ah
440 9.3 Ah
441 8.8 Jo
444 88Ch
444 9.2 Ah
446 88Jo
450 8.0 Jo
456 8.5 Ah
464 83 Ah
467 84Jo
469 8.3 Jo
471 8.0Jo
473 7.8Ah
473 8.0 Pt
475 78Ah
480 7.5 Pt
484 7.5Jo
487 7.1B
RS Sco
164844
415 10.5 Ht
421 10.4Ht
428 98 Ht
443 6.7 Dr
453 6.3 Ht
454 7.0 En
455 61Dr
RR s¢ 0
165030a
415 63 Ht
421 59Ht
428 57Ht
443 5.6 Dr
453 5.9Ht
454 6.2En
455 5.5S]l
455 5.7 Dr
SS Opn
105202
469 11.5 Md
473 98 Pt
480 9.5 Pt
495 9.0 Md
RV Her
165631
423 12.3 L
440 9.5 Jo
444 96Jo
444 97Ch
445 10.6L
J.D.Est.Obs.
RV Her
446
446
448
452
461
466
466
469
469
473
476
480
480
482
484
487
487
490
493
495
496
RT
454
505
RT
444
493
165631
99 Pc
99 Fd
9.7 Jo
98 Jo
10.3 L
9.9 Jo
98 Bw
10.6 Md
98 Jo
9.9 Pt
10.3 L
9.6 Pt
9.9 Bw
10.3 Fd
10.1 Mg
10.2 B
10.1 L
10.4 Jo
10.2 Mg
11.4 Md
11.4 Jo
Sco
165636
12.4 En
R Opn
170215
7.0L
7.6 Jo
8.0 Ch
8.0 L
8.0 Jo
8.3 Fd
9.8 Jo
10.9 Gy
Her
170627
[12.9 Ch
[12.8 Mg
a Her
474
476
171014
3.0 Me
2.9 Mc
Z Oru
473
477
480
171401
11.9 Pt
12.0 Fd
11.9 Pt
418
Monthly Report of the American Association
VARIABLE STAR OBSERVATIONS RECEIVED DurING May AND JUNE, 1931.
J.D.Est.Obs.
T Her
J.D.Est.Obs.
RS Her
171723
441 10.3 Jo
446 10.0 Jo
450
453
456
466
466
469
473
475
480
480
493
495
496
Ca
h
Duy
2c
NIN 90 90 90 90 90 90 90 G0 $9 10}
s
i)
by & iv in & BOO
yn
173643
443 11.1 Dr
455 11.0 Dr
W Pav
174162
415[13.0 Ht
428[13.0 Ht
443[13.4 Dr
J.D.Est.Obs.
W Pav
174162
455[13.6 Dr
RS Opn
174406
473 11.1 Pt
480 11.1 Pt
U ARA
174551
415 13.0 Ht
428[13.0 Ht
443[13.4 Dr
455[13.5 Dr
RT Opu
175111
446 9.7 Fd
446 98Pc
473 10.5 Pt
480 10.6 Bw
480 10.7 Pt
489 10.8 Bw
496 10.8 Bw
510 11.4 Bw
RY Her
175519
423 10.4L
421 10.3 3 Ht
428 10.6 Ht
443 11.4 Dr
461
466
466
467
469
471
471
473
473
475
475
475
476
477
479
479
482
487
496
501
505
180531
11.4L
10.7 Fd
9.5 Me
97 Jo
9.6 Jo
9.4 Me
9.4Jo
9.3 Pt
9.3 Ah
8.8 Fd
9.2 Ah
9.1Vh
8.8L
9.4GD
8.7 Gy
9.3 Be
8.9 Fd
8.3 L
a2 Jo
i2 Ft
8.0 Gy
W Dra
423
447
476
423
446
476
180565
180666
11.0L
11.7L
3.3 1.
V Her
181031
We he
12.9L
13.41.
RY Orn
474
181103
8.0 Dr
8.3 Me
J.D.Est.Obs.
SV Her
182224
425 14.2L
446 14.0L
473 13.0 Pt
476 13.2L
489 12. 7 Bw
495 12.5 Bw
501 11.9 Pt
T Ser
182306
473 12 4 Pt
489 11.5 Bw
496 11.5 Bw
501 11.0 Pt
SV Dra
183149
423 14.1L
448 14.4L
477 14.5L
RZ Her
183225
423 9.5L
446 9.9L
476 11.9L
X Opn
183308
25 273i.
444
445
447
447
449
450
456
467
471
473
476
484
487
497 68 Aw
501 6.9 Pt
503 6.6Aw
RY Lyr
184134
423 11.0L
446 10.4L
473 11.8 Pt
476 11.8L
501 12.2 Pt
tt lt
o>) mae -@
WOMUADADOONWWOR
roo
ye
\
ANNAN NAAANNNNNN
TO
>
=
=
R Scr
184205
423 6.4L
445 5.5L
447 5.5 Fd
449 5.6Fd
449 5.6Me
450 5.4Pe
450 5.6Jo
J.D.Est.Obs.
x. Scr
184205
450 5.6Pt
451
451
454
455
455
456
460
465
466
471
471
472
474
474
475
475
476
wn
os
2m
ioe’
»
oh de
ike) or SO gar
DtnpwUMnQNndDApRWUBRN OH
waes
477
477
477
479
479
480
481
485
485
486
487
488
488
489
493
495
501 5.
503 5.9 Pt
504 5.8 Wd
Nov AOL
184300
450 11.7 Pt
471 11.7 Pt
AMUMUnuUniwnini nnn wiwnonim wn ure
a vrvvs
ag a
C0 to tn DO DOW NAMAWwWROOM
°
gud
MANNION On ON UT Tt
—oP ee OQ ot et
© 00
ya
TUN
_
479 11.8 Pt
497 11.7 Pt
501 Lis Pt
RX Lyr
185032
473 13.0 Pt
501 13.5 Pt
R Lyr
468
J.D.Est.Obs.
S CrA
1854374
428 11.9 Ht
451 11.5S1
453 11.7 Ht
455 12.7 Sl
ST Scr
185512a
477[12.5 Fd
R CrA
1855374
428[12.5 Ht
451 11.7 Sl
453 12.5 Ht
455 11.9 SI
T CrA
185537b
428[12.5 Ht
451 13.0S1
455 13.0SI1
Z Lyr
185634
423 13.8 L
446 13.8L
473 11.4 Pt
476 11.7 L
491 10.2L
501 10.0 Pt
SU Scr
185722
428 8.6Ht
453 8.4 Ht
456 10.5 Ah
473 11.1 Pt
475 11.1 Ah
501 11.4 Pt
V Lyre
190529a
450 14.0 Fd
RX Sar
190818
428 10.5 Ht
445 10.0L
447 10.2 Pt
453 9.9 Ht
460 9.6Ch
475 10.1 L
501 11.0 Pt
cn +
em a SO De
VARIABLE STAR OBSERVATIONS ‘RECEIVED DurING MAy
J.D.Est.Obs.
RW Scr
1908 19a
423 9.6L
428 9.6 Ht
445 9.4L
447 98 Pt
453 9.6 Ht
460 9.6Ch
475 9.6L
501 9.0 Pt
TY AQ.
190907
447 10.3 Pt
501 10.2 Pt
S Lyr
190925
479[12.3 Gy
505[12.9 Gy
X Lyr
190926
473 9.0 Pt
501 8.8 Pt
RS Lyr
190933a
425 10.9L
446 12.1L
489[13.4 Bw
505[12.7 Gy
U Dra
190967
5 1394,
8 13.8 L
191007
446 11.4L
475 11.8L
501 12.2 Pt
T Sar
191017
447 10.8 Pt
460 11.3 Ch
501 11.8 Pt
R Ser
IQIOIQ
425 68L
428 7.1Ht
446 7.0L
447 5 Pt
449 5 Me
453 5 Ht
4.
J
00 00 CO SININININININS
mu
J.D.Est.Obs.
RY Scr
191033
428[12.5 Ht
443 12.5 Dr
451 12.3 Sl
453 12.5 Ht
454 12.7 Dr
455 11.981
475 11.8L
481[12.0 Pt
487 11.6L
489[12.0 Pt
501[12.0 Pt
507[11.5 Pt
TY Scr
455 11.7 Dr
S Scr
191319a
425 10.2L
428 10.8 Ht
446 11.1L
447 P
449
453
455
477
TON eed!
SD tm tne Go Go
+
NX
aN
—
N
i
oN
F
»L
SW “Scr
191331
13.1 Dr
446 10.6 Fd
446 10.7 Pe
473 10.0 Pt
501 10.5 Pt
U Lyr
191637
10.9 Jo
10.7 Jo
447 10.8 Fd
450 10.6 Jo
> 10.6 Jo
10.7 Fd
7 10.9Jo
10.8 Jo
10.0 Pt
10.6 Fd
2 10.8 Fd
10.7 Jo
44]
446
t
Te
It
fe
d
J.D.Est.Obs.
AF Cyc
192745
444 68Ah
448 69 Ah
456 6.5 Ah
463 6.4Ah
464 65Ah
473 6.6 Ah
475 66Ah
LY Cye
192928
429 10.2 L
446 9.9L
477 10.3 L
491 10.5L
501 10.8 Pt
RT Aor
193311
426 14.21
193449
447 13.5 Pt
501 14.0 Pt
RV Aor
193509
426 11.1L
447 93Pt
448 9.9L
477 10.1L
491 10.9L
501 11.5 Pt
T Pav
193972
12.0 Ht
12.0 Ht
11.3 He
10.2 S1
10.1 Dr
8.6 Ht
415
421
428
443
443
453
455
x "Cya
_
ek ek et et et OOS
WSOP HNKENNE
44]
446
447
450
456
+t
N
4.
—
BSN
“SJ
un
by mio Nitin dd NO ONNYE
1
BSS
22
o
SINT OO C0 90
coYTIC
J.D.Est.Obs.
TU Cyc
194348
14.1 L
13.1 Pt
448 144L
476 12.8L
501 10.9 Pt
X AOL
194604
429 148 L
448[14.4L
477[14.4L
x Cyc
194632
447 13.5 Pt
451[13.4 Ma
479 12: 9 Bg
479
482
484
495
499
501 10. 2 Pt
S Pav
194659
8.1 Dr
7.6 Dr
RR Scr
1949020
7.2 Dr
426
447
443
447 12.3 Pt
448 120L
477 13.4L
RS AOL
195308
3.8L
J.D.Est.Obs.
Zz Cye
195849
448 13.2L
476 14.5 L
501 12.4 Pt
S Tet
195855
428[12.6 Ht
453 12.8 Ht
SY Ao.
200212
425 12.8L
448 13.0L
477{14.3 L
S Cyc
200357
447 12.6 Pt
479[12.3 Gy
R Cap
200514
Rue hs
S AOL
200715a
447 9.6 Pt
449 9.5 Fd
449 9.6 Me
455
472 1
477 11.5
501 11.6 Pt
RW Aor
200715b
447 93 Pt
501 9.2 Pt
R Tex
477
AND JUNE,
9.8 Me
1.2 Me
Me
1931.
J.D.Est.Obs.
mS (ve
200938
+
Re
po 90 ONL
I
8 OW d
8.4 Jo
7.6 Pt
8.8 GD
R Der
201008
10.5L
11.1 Pt
119 kL
501
501
425
447
448
447 68Pt
449 7.9Fd
477 8.2Fd
SX Cyc
201130
447 10.0 Pt
501 12.2 Pt
RT Scr
201139
443 9.7 Dr
455 89 Dr
WX Cyc
201437b
425 11.51
441 10.7 Jo
445 10.8L
446 10.5 Jo
447 10.5 Pt
450 10.4 Jo
456 10.7 Jo
461 10.7 L
467 10.4 Jo
471 10.5 Jo
477 10.7 L
491 9.7L
496 10.6 Jo
501 9.1 Pt
201
441 8
446 Pa]
447 8
449 8
450 88 Jo
455
456
9.0 Jo
420
Monthly Report of the American Association
VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND Jung, 1931.
J.D.Est.Obs.
U Cre
201647
469 87Jo
471 88Jo
474
477 1
478
479
482
487
487 10.
489
495
496
501
504
wovyeyyrss
DOD DWDM wW~
AQ2nts2nN2z
bed Lm —
~ Ts) Qo. ata
202240
443 81Dr
455 8.3Dr
RW Cyc
202539
455 83Me
Z DEL
202817
426 12.9L
448 11.5L
477 9.3L
491 88L
501 9.2 Pt
ST Cye
202954
429 11.0L
447 10.6 Pt
448 10.9L
449 11.2 Fd
471 11.0 Jo
477 10.4L
479 10.6 Gy
498 10.5 Gy
501 10.8 Pt
V VuL
203226
447 89 Pt
501 86 Pt
Y Dex
203611
429 14.0L
477 13.8L
S Det
203816
447 92Pt
501 88Pt
J.D.Est.Obs.
V Cye
203847
477 13.3 L
501 13.6 Pt
Y Aor
203905
449[12.0 Fd
485[12.3 Fd
T Det
204016
425 11.4L
447 12.5 Pt
448 12.4L
477 12.9L
503 14.5 Pt
V Aor
204102
429 85L
447 8.0L
454 86L
486 8.6L
W Aor
204104
426 10.5L
454 10.2L
486 9.6L
U Cap
204215
486/13.5 L
T Aor
204405
447 92Pt
449 90Fd
485[12.3 Fd
RZ Cyc
204846
447 12.1 Pt
449[12.4 Fd
485 11.6 Fd
503 11.3 Pt
S Inp
204954
428[13.1 Ht
443[13.8 Dr
455[14.0 Dr
X DEL
205017
425 12.4L
448 12.8L
486 14.2L
RR Cap
205627
455 13.8 Dr
T Oct
205782
441 13.1 SI
443 13.0 Dr
451 13.4 Sl
J.D.Est.Obs.
R Vut
205923a
447 9.5 Pt
450 9.0Jo
456 88Jo
456 8.9 Ah
474 9.1 Me
475 9.0 Ah
496 10.5 Jo
503 11.5 Pt
V Cap
210124
505[12.5 Gy
TW Cyc
210129
429 12.0L
448 12.6L
486 12.1 L
RS Aor
210504
454 12.3 L
486 11.4L
503 11.0 Pt
R Eou
210812
429 13.9L
448 11.9L
503 10.5 Pt
T Cep
210868
433 8.6A h
434 87Ah
35 87 Ah
439 87Ah
440 88Ah
440 82Jo
443 8.5 Jo
444 89 Ah
446 8.7 Jo
446 9.2 ( IV
447 86Pt
447 90Fd
448 9.1Ah
449 93Fd
450 8.9 Jo
451 9.5 Gy
453 9.1 Jo
456 9.3 Ah
466 9.4Fd
466 9.2Jo
471 93]Jo
475 9.9 Ah
475 9.4Fd
477 9.7 Fd
479 98 Gy
481 9.6 Pt
482 9.5 Fd
485 9.5 Fd
486 12.8L
490 9.6Jo
J.D.Est.Obs,.
T Cep
210868
496 98Jo
498 10.0 Gy
RR Aor
210903
425 9.5L
445 10.5L
447 10.6 Pt
477 129L
481 12.6 Pt
Y Pav
211570
428 5.5Ht
453 58Ht
X PEc
211614
426 11.5L
21 3678
447 11.7 Pt
449 12.2 Fd
481 11.8 Pt
485 11.8 Fd
RU Cyc
213753
434
439 7.
440 7.9 Ah
444
447 7
456 7
474 8
474 7
475 7
447 6.7 Pt
J.D.Est.Obs.
RR Pec
214024
449[12.6 Fd
487 13.0 Pt
R Gru
214247
455 11.9Dr
V Pec
215605
426 10.5L
449 11.7 Fd
454 12.2L
486 13.6L
U Aor
215717
486[12.2 L
RZ Perc
220133b
426 9.3L
448 9.2L
450 9.1 Pt
461 9.1L
486 9.4L
487 9.5 Pt
T Pre
220412
426 9.7L
454 9.5L
486 9.7L
505 11.0 Gy
RS Perc
220714
454 13.5L
486 13.3L
S Gru
486 128L
J.D.Est.Obs.
R Lac
223841
429 14.0L
454 13.4L
486 9.7L
RW Perc
225914
454 12.3L
485 10.2 Fd
486 10.5 L
487 10.0 Pt
R Pec
230110
479 11.6 Gy
487 12.0 Pt
505 11.5 Gy
V Cas
230759
456 85 Ah
447 85 Pt
475 78Ah
488 7.2Pt
W Pec
231425
429 10.7 L
454 10.5L
477 9.1Fd
486 8.9L
S Perc
231508
454 9.0L
486 10.5 L
488 10.5 Pt
V PHE
232746
455 99Dr
Z AND
232848
395 10.0Rs
450 10.2 Pt
474 10.4 Me
488 10.4 Pt
ST ANpb
233335
447 9.0Pt
477 9.2 Fd
485 8.9 Fd
488 8.9Pt
Z Cas
233956
377[12.1 Gh
424 13.7 L
454 11.3L
485 11.0 Fd
486 11.2L
R PHe
235150
455[12.9 Dr
of Variable Star Observers
VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND JuNE, 1931.
J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs. J.D.Est.Obs.
R Tuc R Cas R Cas R Cas R Cas Y Cas
235205 235350 235350 235350 235350 235855
411[13.3Ht 419 62Wd 425 67Jo 436 7.2Jo 479 85Gy 425 116L
421[13.0Ht 419 66Jo 427 63Ah 439 66Ah 495 80Gy 454 11.5L
455{13.5Dr 420 63Ah 428 64Ah 440 66Ah Z PEG 486 11.6L
R Cas 421 64Ah 431 65Ah 440 7.5Jo 235525 SV AND
235350 422 61Wd 433 65Ah 446 7.5Jo 454 82L 235939
62Ah 422 66Jo 434 65Ah 450 7.5Jo 486 9.3L 488 11.2 Pt
6.2Ah 424 64Ah 435 65Ah 456 7.2Ah 488 9.1 Pt
RAPIDLY VARYING IRREGULAR VARIABLES.
Star J.D. Est.Obs. J.D. Est.Obs. Star J.D. Est.Obs. J.D. Est.Obs.
005840 RX ANpDROMEDAE— 074922 U GeMINoRUM
6450.97 11.5 Pt 6488.9 13.1 Pt 6447.5 9.9 Gh 6452.6 13.3 GC
6487.9 12.3 Pt 6489.9 12.6 Pt 6447.5 10.0 Rs 6452.9 13.5 Sl
060547 SS AvurRIGAE— 6447.9 98SI 6453.6 13.5 Bg
6419.6[13.2 Gh 6455.6 11.2 Me 6448.5 10.1 Rs 6453.6 13.2B
6423.6 14.7 L 6458.1 11.3 Ch 6448.5 10.0 Gh 6453.9 13.6 Sl
6425.6[14.5 L 6459.6 11.1 Bg 6448.6 10.3 Ge 6454.4 13.6 L
6426.6[13.9 L 6459.8 11.3 Pt 6449.6 11.0B 6457.6[13.0 B
6429.4[12.5 L 6460.6 11.1 Bg 6449.7 10.9 Me 6459.6[13.3 Bg
6430.3[12.5 L 6460.7 11.3 Me 6449.7 11.0 Ke 6465.6[13.3 Bw
6431.3[13.3 L 6461.3 11.0 L 6449.9 11.0 S1 6467.4 13.6 L
6437.1[13.3 Ch 6461.6 11.3 Me 6450.3 11.4 L 6467.6[13.8 B
6442.4 14.7 L 6461.6 11.3 Bg 6450.6 12.0 Pe 6467.7[12.7 Me
6443.3[14.5 L 6462.6 11.8 B 6450.6 12.0 Be 6469.6 13.5 Mg
6444.6[12.5 Mp 6462.7[12.0 Pt 6450.6 12.3 Rs 6470.6 14.01
6445.6[13.9 B 6465.6 13.6 Bw 6450.7 11.6 Me 6473.6 [126 Me
6446.3[13.9 L 6466.7[12.6 Pt 6450.9 12.3 SI 6473.7[13.3 Mg
6447.3[13.9 L 6467.3 14.2 L 6451.1 12.5 Ch 6474.7[12.7 Me
6447.7[13.5 Pc 6469.6[13.2 Mg 6451.6 12.8 GC 6475.6[13.8 Mg
6448.5[12.6 Gh 6470.7112.7 Me 6451.6 12.8 Bg 6478.6 13.9B
6449.6[13.9 B 6473.6[13.9 Mg 6451.6 12.5 Rs 6479.6 13.7 Be
6449.8[12.6 Pt 6474.7[12.6 Me 6451.6 12.3 Gh 6480.6[13.3 Bg
6450.3 14.5 L 6475.6{13.2 Mg 6451.6 12.8 Mg 6480.6/13.3 Bw
6451.1 13.2 Ch 6478.7[12.5 Me 6451.7 12.7 Me 6489.6[12.4 Bw
6451.6 12.7 Rs 6479.6[13.9 Bg 6451.9 13.0 SI 6496.6[12.4 Bw
6451.6 12.7 Gh 6479.8[12.0 Pt 081473 Z CAMELOPARDALIS
6451.6 12.8 Mg 6480.7[12.0 Pt 6423.4 11.2 L 6455.6 11.8 Me
6451.7 12.5 Me 6481.7[12.6 Pt 6425.4 11.2L 6460.4 11.5 An
6452.6 11.9 Me 6482.6[13.2 Mg 6426.3 11.6 L 6460.4 11.6 Be
6453.6 116B 6494.7[11.0 Pt 6428.3 11.7 L 6461.3 11.4L
6453.6 11.8 Rs 6501.7[12.6 Pt 6429.4 11.7 L 6461.6 11.7 Bg
6454.4 10.9L 6430.3 11.7 L 6465.4 12.6 Md
074922 U GemInoruM— 6431.3 11.8 L 6465.6 12.6 Me
6423.4 13.7 L 6443.0 9.5 SI 6438.2 11.2 Ch 6466.7 12.7 Me
6425.4 13.7 L 6443.4 9.0L 6439.6 12.1 Ke 6467.4 12.3 L
6426.3 13.8 L 6444.0 9.6 SI 6442.4 11.4L 6467.7 12.8 Me
6428.3 13.8 L 6444.2 9.3Ch 6442.6 11.4L 6468.7 12.6 Me
6431.4[10.9 L 6444.6 9.5Gh 6445.3 11.7 L 6469.7 12.8 Me
6435.9 9.0S1 6445.3 9.0L 6446.3 11.8 L 6470.7 12.8 Me
6436.1 9.1 Ch 6445.6 9.2Gh 6447.3 11.7 L 6471.6 12.1 L
6436.9 9.0SI1 6445.9 9.7 Sl 6449.7 11.8 Me 6471.7 13.0 Me
6437.9 9.0S1 6446.3 9.1L 6450.3 11.8 L 6472.3 12.5 L
6438.7 9.6 Ke 6446.5 9.5 Gh 6450.7 12.1 Me 6472.7 12.8 Me
6440.0 9.0SI1 6446.5 9.5 Rs 6451.6 12.1 Bg 6472.9 12.6 Me
6440.9 9.3 Sl 6446.7 9.6 Fd 6451.7 12.3 Me 6473.6 13.0 Me
6441.9 94S] 6446.7 10.0 Pc 6452.6 12.2 Me 6474.7 11.4 Me
6442.4 9.3L 6447.3 9.3L 6454.4 11.6 L 6474.7 11.4Vh
422
Monthly Report of the American Association
Star J.D. Est.Obs.
VARIABLE STAR OBSERVATIONS RECEIVED DurING MAy AND JUNE, 1931.
J.D. Est.Obs.
081473 Z ‘\CAMELOPARDALIS
Star
J.D. Est.Obs.
213843 SS Cyen1—
6474.8 11.3 Vh 6480.7 11.7 Me 6439.4 9.7 Ah
6474.8 11.4 Me 6481.7 11.7 Me 6440.5 9.6 Ah
6474.9 11.2 Me 6482.7 11.7 Me 6441.8 9.7 Jo
6475.6 10.8 L 6483.7 11.9 Me 6442.6 9.7L
6475.7 10.9 Me 6484.6 12.0 Bg 6444.5 10.2 Ah
6475.7 10.9 Me 6484.7 11.9 Me 6445.6 10.1 L
6475.7 10.8 Vh 6485.8 11.9 Me 6446.6 10.2 L
6476.4 10.7 L 6486.5 11.5L 6446.7 10.7 Fd
6476.7 10.9 Me 6486.7 12.1 Me 6446.8 10.3 Jo
6476.7 10.9 Me 6487.5 12.2L 6446.8 10.7 Pc
6476.7 10.9 Vh 6487.7 12.2 Me 6447.8 11.6 Pt
6477.6 10.9 L 6488.9 11.7 Me 6447.8 11.0 Fd
6477.8 11.2 Me 6489.9 12.0 Me 6448.6 11.3L
6478.7 11.5 Me 6490.7[11.9 Me 6449.8 11.8 Fd
6479.7 11.6 Me 6491.5 12.3 L 6449.8 11.7 Pt
6479.6 11.4 Bg 6497.7 12.6 Me 6449.9 11.8 Me
6480.6 11.2 Bg 6499.6 11.0 Bg 6450.8 12.0 Fd
094512 X Lreonis— aaa a ; r
6447.6 12.2B 6474.4 12.4 Be 6450.9 117 Pt
6451.6 13.3 B 6479.6 12.4 Bg woe cote
aos id : <a 6451.8 11.9 Ma
6445.7[11.8 Pt 6480.6 12.5 Be 6454.6 11.61
6467.6[13.4 B 6499.6[12.6 Be 6455.0 118 Me
202946 SZ Cycni— 6456.5 11.5 Ah
6447.8 9.0 Pt 6481.7 9.6 Pt 6456.8 12.0 To
6449.8 9.5 Pt 6485.8 9.6 Pt 6460.4 11.7 Ch
6450.8 9.0 Pt 6487.9 9.2 Pt 6460.8 11.6 Ma
6466.7 9.6 Pt 6488.9 9.0 Pt 6461.6 11.1 L
6467.7 9.6 Pt 6489.9 8.8 Pt 6461.8 11.4 Ma
6471.8 9.6 Pt 6490.7 9.0 Pt 6465.8 10.2 Ma
6472.7 9.4Pt 6493.7. 9.0 Pt 6466.9 10.1 Ma
6473.7 9.0 Pt 6494.7 9.4 Pt 64678 9.2Ma
6475.7 9.0 Pt 6501.7 9.3 Pt 6470.8 10.2 Ma
6479.8 9.0 Pt 6503.8 9.3 Pt 64716 10.2L
6480.7 9.2 Pt 6471.7 10.7 Jo
213843 SS Cyreni— 6471.8 10.4 Pt
6423.7 11.4L 6426.7 11.5 L 6472.7 10.8 Pt
6425.7 11.4L 6429.6 11.4L 6472.9 10.4 Me
SUMMARY OF OBSERVATIONS FOR MAy AND JUNE,
Observa-
Observer Initial Vars. tions Observer Initial
Adwell Aw 1 : Godfrey Club GD
Ahnert Ah 35 199 Gooch Gh
Allen, P. R. Al 7 9 Gregory Gy
Ancarani An 8 8 Houghton Ht
Baldwin Bl 54 116 Jones Jo
3enini Be 9 18 Kline Ke
Bigelow Bw 20 52 Lacchini #
Boutell BL 16 95 Marsh Ma
Bouton 3 69 105 McLeod Mc
Buckstaff 3c 9 11 McPherson Mp
3unting Bg 27 66 Meek Me
Chandra Ch 86 105 Mennellay Mn
Dartayet Dr 82 150 Monnig Mg
Dawson Dw 10 12 Millard Md
Ensor En 67 240 O’Byrne Oy
Ford Fd 62 124 Peltier Pt
Georgetown GC 10 22 Proctor Pe
J.D. Est.Obs.
6473.4 10.7 Ah
6474.8 11.4 Me
6475.5 11.3 Ah
6475.6 11.4L
6475.7 11.6 Pt
6475.7 11.7 Fd
6476.8 11.6 Ma
6477.6 11.5L
6477.7 11.5GD
6477.8 11.7 Fd
6477.8 11.6 Me
6479.8 11.7 Pt
6480.7 11.7 Pt
6481.9 11.7 Pt
6482.7 11.6 Me
6485.8 10.6 Me
6485.8 10.3 Fd
6485.8 10.5 Pt
6486.6 10.2 L
6487.6 9.8L
6487.9 10.3 Pt
6488.1 9.8Bec
6488.9 10.0 Me
6488.9 10.0 Pt
6489.9 9.9 Pt
6493.7 11.5 Pt
6494.7 4 7 Pt
6495.6 11.3 Wd
6495.6 11.3 Bg
6499.6 11.1 Bg
6501.7 11.7 Pt
6503.8 11.7 Pt
6504.7 11.2 Wd
6510.7 8.5 Jo
6510.8 8.4Ma
6511.7 8.4Ma
6512.7 8.4Ma
1931.
Observa-
Vars. tions
8 16
5 13
29 48
77 261
63 349
26 58
159 566
8 24
16 42
7 13
54 168
6 8
31 56
9 23
3
181 425
34 44
Notes from Amateurs
Observa- Observa-
Observer __[nitial Vars. tions Observer Initial Vars. tions
Ross Rs 4 9 Vorhies Vh 8 15
Shinkfield Sl 36 88 Wares Ws 7 11
Shultz Sz 7 7 Webb Wd 19 80
Smith, F.W. Sf 10 33 Wright Wr 1 1
Taffara Tf 4 11 — —_—
Theile Th 6 41 Totals 44 413 3752
servatory. Requests for charts may be addressed to Mrs. Helen S. Hogg, Astro-
physical Observatory, Victoria, B. C., Canada. Mr. Raymond Boyd, of Glen
Ridge, New Jersey, is spending the summer at Harvard Observatory getting ini-
tiated into the mysteries of variable stars, observationally, as well as by discussion
of the observations themselves.
As reported in the A.A.V.S.O. Bulletin, all three of the well-known SS Cygni
type variables have been in the lime-light recently. This applies paticularly to
SS Cygni itself, which passed through a normal long type maximum late in June,
following a series of three anomalous maxima in quick succession.
July 8, 1931. Leon CAMPBELL, Recording Secretary.
NOTES FROM AMATEURS
Amateur Telescope Makers of Chicago
The regular monthly meeting of this organization was held at the home of
Mr. F. W. Nack, where we had the pleasure of examining his 24-inch and 10-inch
Cassegranian reflectors. His machine for grinding and polishing large mirrors
was a center of attraction.
The well-known telescope maker, John E. Mellish, our technical adviser, as
usual tested all mirrors that the members had brought and gave advice on the
many problems and difficulties an amateur telescope maker meets with.
Anyone interested in this organization can obtain information from the
President, Mr. G. McCord, 220 Linden Avenue, Oak Park, Illinois.
Baltimore Astronomical Society
In the winter of 1930 the old and dormant “Baltimore Astronomical Society”
was reestablished and reorganized by six members of The Maryland Academy of
Sciences. Since then its membership has more than trebled and its activities have
continually increased. Under the auspices, and through the kindness of the
Academy, the Society is afforded the use of meeting rooms and a revolving domed
observatory equipped with a splendid Alvan Clark, 8-inch, refracting, clock-driven,
equatorially mounted telescope, accompanied by many valuable accessories.
The purpose of the Society is of a threefold nature. The first is the com-
panionship, pleasure and increase of astronomical knowledge gained by its mem-
bers. This is accomplished by regular bi-monthly meetings, at which a rather
definite course of reading and observing is followed. When weather conditions
interfere with observing the time is given to discussions and to showing slides
of celestial objects. In this manner the members enjoy many evenings. The sec-
and third parts of the Society’s purpose are interwoven by its assistance to the
interested public and to the Academy. This is made possible by “Open House” of
the observatory, atop the Hall of the Academy, held every clear Thursday even-
ing. On these evenings it is not uncommon to answer hundreds of general astro-
424 Notes from Amateurs
nomical questions and to assist hundreds of interested people to view the wonders
of the sky. In this way interest in astronomy and contact with the well-known
“Maryland Academy of Sciences” is encouraged. Although no technical work is
undertaken by the Society, it has met with much success and encouragement for
its humble endeavor to further the interest in, and knowledge of, the science of
astronomy.
The Society and the Academy extend a cordial invitation to all those inter-
ested to visit them atop the “Hall of the Academy” any clear Thursday evening.
3947 Boarman Ave., Baltimore, Maryland. Joun M. Croruers.
An Outdoor Observatory
We received an interesting post card recently bearing a photographic print
having: features as follows: a level open field sparsely covered with clumps of
grass; in the background, a row of trees and low shrubbery; in the center, a
telescope on a tripod, apparently easily portable; on one side of the tripod, a low
table with papers, presumably star charts and note paper, lying on it; on the other
side, under the eyepiece, a box no two of whose dimensions are equal.
On the reverse side of the card were the sender’s comments: “As you have
been publishing accounts of inexpensive observatories, I thought you might like
this picture of mine, located at Scipioville, Merrifield P. O.,. New York. Atten-
tion is called to the dome, which is simplicity itself, and revolves automatically.
Also the effect of a rising floor is secured by use of a box, on the side, edge or
end of which the observer sits, or for objects very near the horizon, he lays it flat
and stands on it. Atlas equipment consists of Schurig’s and Beyer-Graff maps,
and charts of the A.A.V.S.O. Weather protection is secured by alternate layers
of wool and fur fabrics, over which on some nights a quarter inch of hoar-frost
is thrown. Freedom from interfering lights and smoke is provided by locating on
high ground twelve miles from any city. The glass is a 5-inch Clark refractor,
equatorially mounted, the property of the A.A.V.S.O. With it stars of mag. 12.9
have been observed, and such objects as the Cluster in Hercules are beautifully
broken up. Visitors are welcome, by appointment, any clear night; at least two
hundred have already been introduced to the celestial world here. Caspar R.
Gregory. Telephone Poplar Ridge 7-F-21.”
America’s First Planetarium
A planetarium is, of course, an indoor sky-show where sky stars are shown
on a curved ceiling. It was only last year that Chicago opened its wonderful
planetarium. Philadelphia will shortly have one of its own. St. Louis has hopes
in the same direction, as have also the culturally proud people of other cities. For
beating Philadelphia and other cities to it, Chicago has much cause for its astro-
nomical jubilation. But why the unseemly boasting over New York?
Millions know that New York has had a planetarium—free to the public—
since February 2, 1913! Besides, its stars twinkle, as all good planetarium stars
should do—in addition to having standing room for 30,000 people! Every 24
hours, thousands gather beneath its begemmed Mediterranean-blue vaulted ceiling
preparatory to dispersing to all parts of the world! The winter signs of the
Zodiac there shown are Aquarius, Pisces, Aries, Taurus, Gemini and Cancer—125
feet above the Concourse, Grand Central Terminal. The New York Central Rail-
road Company was the first throughout the world to thus honor the stars by so
beautifying a railroad station.
77 Heller Parkway, Newark, New Jersey.
Henry Ditt BENNER.
Zodiacal Light Notes
ZODIACAL LIGHT NOTES
By W. E. GLANVILLE.
EvENING ZopiAcAL LicguHt.—Continuing his observations, Mr. Stuart L.
O'Byrne, Webster Groves, Missouri, sends reports for April 22, 26, 28, and May
15. On April 22 at 7:40 he noticed a band of light from the northwest through
west to southwest along the horizon and visible as far as 12° above horizon—
probably the last vestige of ordinary twilight. On April 26 at 7:58 he found the
Light faintly visible in Taurus, Perseus, and Aurigae, but boundaries were too
diffuse to be determined, due no doubt to moonlight. On April 28 the moon again
interfered but he found a faint area in the western sky near the ecliptic, spread
over the northern part of Taurus. On May 15 at 8:25 the Light was fairly well
defined, covering a region in Gemini, Taurus, and Aurigae. The bright central
portion lay between 8 Tauri and the apex about two degrees east of TGeminorum.
At 8:30 the Light was fading rapidly. In these reports the greater part of the
Light was north of the ecliptic.
Since his last report the writer has observed the Light on the following eve-
nings: May 16, June 8, 11, 16, 17, and 18. All other moonless evenings were
overcast. On May 16a slight general haze was noticed at 8:20 but the Light was
fairly distinct. The apex was about five degrees north of Jupiter in Gemini; the
south boundary passed about three degrees north of yGeminorum; the north
boundary from the apex over to eight degrees south of Capella. 8 Tauri was very
near the central line of the luminous area. Breadth along the -horizon, 35°. On
June 8 at 9:30 with Castor and Pollux near the northwest horizon, the Light was
somewhat faint and fairly equal in luminosity along the horizon. The apex was
noted near Regulus and Mars and was blunted. At 10:30 no trace of the Light
remained but at that time an aurora was seen from the feet of Ursa Major thence
below Polaris to Cassiopeia. It was specially marked by a bold, steady column
rising 30° from the horizon and situated about half-way between the meridian
and Ursa Major. On June 11 at 9:20 the Light was fairly strong. The south
boundary ran towards Regulus to the apex in the Sickle. Irom the apex the
north boundary spread over to the Lynx Pair thence broadening to the horizon.
At 9:50 the apex was clear of the Sickle northwards. Again the main body of the
Light was north of the ecliptic. On June 16 at 9:15 the sky was crystal clear
after thunderstorms and heavy showers most of the day, but, notwithstanding the
exceedingly clear sky, the Light was very faint from Jupiter in Gemini around the
northwest to the horizon below Polaris. The blunted apex was partly within,
partly without the northern boundary of the Sickle. At 10:00 p.m. scarcely any
trace of the Light was visible. On June 17 at 9:15 a general slight haze over-
spread the sky and the Light was considerably stronger than it was the preceding
evening. At 10:00p.m. the Light still continued strong. The sloping, blunted
apex now covered the Lynx Pair and the northern boundary now skirted the
horizon on past the meridian to the northeast. Altitude of Light along north
horizon averaged 10°. On June 18 the sky was somewhat hazy at 9:20 and the
Light fairly strong with the apex partly in the Sickle and partly northwards. As
on recent evenings the northern boundary sloped gradually to the north horizon
below and eastward of Polaris.
MorninG ZoprAcAL Light.—On June 18 at 2:45 the Light was observed lying
426 General Notes
along the northeast and east horizon just below the Aries asterism on to the
eastern part of Aquarius, south of a Pegasi. Average breadth along the horizon
was about 15°. On June 19 the Light was again observed from 2:30 to 3:00 a.m.
lying along the horizon below Perseus and tapering to a point below a Pegasi. The
Light strengthened but remained within bounds until 3:00 A.m. when the Perseus
and Aries stars faded as dawn came. In tropical latitudes, instead of lying along
the horizon, this morning Light in June would be seen making a high angle with
the eastern horizon. These morning observations continue the series of summer
observations made last year when the Light was watched passing from the north-
west in the evening, round the north as night progressed and on towards the
northeast.
GEGENSCHEIN.—On June 17 at 11:45 p.M., after several minutes’ trial, the
Gegenschein was seen as a hazy bridge spanning the dark area between M 20 on
the edge of the eastern branch of the galaxy, straight across to the western
branch. It was very faint but unmistakable by contrast with the dark gaps above
and below. Estimated breadth was about three degrees. The oval part of the
apparition was probably blanketed by the commingled light in the eastern branch
of the Galaxy. On June 18 the observation of June 17 was corroborated from
11:30 to 11:40.
Zodiacal Light observers have been perplexed by the fact that when the at-
mosphere has been washed clean and the ecliptic makes a rather low angle with
the horizon the Light is very faint (see report for June 16). One might expect
that in an unusually clear sky the Light would be correspondingly strong. Perhaps
some reader can offer a suggestion in explanation of this curious circumstance.
The Rectory, New Market, Maryland.
GENERAL NOTES
Dr. Harlow Shapley has recently had the degree of Doctor of Laws con-
ferred upon him by Oglethorpe University, Atlanta, Georgia.
Dr. R. J. Trumpler, of the Lick Observatory, has been granted a year’s leave
of absence, beginning July 1, for study in Europe.
Sir Arthur S. Eddington, Plumian professor of astronomy and experimental
philosophy in the University of Cambridge, has been elected a foreign member of
the American Philosophical Society, Philadelphia. (Nature, May 30, 1931.)
Dr. Harlow Shapley, director of the Harvard College Observatory, has been
elected an honorary foreign member of the Royal Swedish Physiographic Society
of Lund, and a foreign correspondent of the Royal Lombard Institute of Science
and Letters. (Science, May 29, 1931.)
Dr. Harlan T. Stetson, Professor of Astronomy at Ohio Wesleyan Univer-
sity and Director of the Perkins Observatory, addressed an open meeting of the
Mathematics Club of Oberlin College the afternoon of May 22, on the subject of
“The Influence of the Sun and Moon on Radio Reception.”
General Notes
427
Dr. Frederick C. Leonard, of the University of California at Los Angeles
since 1922, has been appointed Chairman of the newly created Department of
Astronomy in that institution (July 1, 1931).
William F. Denning, the well-known English amateur astronomer and recog-
nized authority on meteors, died in Bristol, England, on June 9 at the age of
eighty-two.
Professor Solon |. Bailey, for many years professor of astronomy at the
Harvard College Observatory, and author of “History and Work of the Harvard
Observatory,” recently published, died on June 5. An account of Professor
aBiley’s work is being prepared by Professor Edward S. King and will appear in
the next issue of this magazine.
Professor Frost’s Sixty-Fifth Birthday Celebration
The Yerkes Observatory was never seen in a happier mood than on July 14,
1931. It was the occasion of the celebration of the sixty-fifth birthday of the Di-
rector, Professor Edwin Brant Frost. In the afternoon more than 350 guests
assembled on the lawn of the Director’s residence to offer their congratulations
and good wishes. There were men and women from all walks of life, bankers,
farmers, tradesmen, as well as doctors, university professors, ministers, and
lawyers, people who carry on the work of the world.
The University of Chicago was represented by the ‘ormer president of the
Board of Trustees, Martin A. Ryerson, by the Dean of the Division of the Phy-
sical Sciences, Henry G. Gale, Professor Arthur Compton, and many others.
There were guests from abroad: Sweden, Czecho-Slovakia, India, and the Philip-
pines. Many who could not be present sent telegrams and cables. So great was
the number that a special operator was sent to the village station to receive the
messages. Over 150 telegrams came on the day of the celebration. There was
even a message from the crews of the two daily trains, which make the run be-
tween Chicago and Williams Bay. Letters came by the hundreds; letters which
were filled with thankful and deep appreciation for the help and inspiration which
Professor Frost had given through the years. Some of them were from friends
of student days in Germany; many from former students at Dartmouth and some
came from boyhood friends in New England, one of them said, “I say to you as
Lowell said to Holmes ‘What has the calendar to do with gay immortals such as
you whose years but emphasize your youth.’” So many letters were received that
it would be impossible for Professor Frost to answer them. It would be a
Herculean task. His friends must accept his silent but heartfelt appreciation.
Beautiful were the tributes paid to Mrs. Frost and Miss Katharine Frost. They
were not unmoved by them.
There were gifts: The staff of the Observatory presented their director with
a handsome watch that strikes the hours, the quarter hours, and the minutes.
From his friends who live on the shores of Lake Geneva came a splendid token
of their appreciation of his leadership in the community and of their affection;
from the village of Wiliiams Bay he received a message addressed to their “most
distinguished citizen.” Arm-loads of flowers, books, candy, and birthday cakes,
six of them, huge cakes with candles, were brought as offerings to the one who
was their “guide, philosopher, and friend.”
In the evening the Observatory was opened to the guests. The 40-inch tele-
scope was used for observing. The news of the celebration was carried far and
428 General Notes
wide by the Press which seemed to have a particular joy in giving this event
recognition.
After all it was the spirit of the man that made the day. There he stood
among his friends who delighted to honor him, one of the best beloved astrono-
mers of the world. .
s t Cuirrorp C. Crump.
The American Astronomical Society will hold its summer meeting at the
Perkins Observatory, Delaware, Ohio, September 7, 8, and 9.
The Napierian Base Scheme of Planetary Distances ( PoruLar ASTRONOMY,
June-July, 1931) has been revised slightly so that the formula contains a term
for the mass of the planet. The average of errors is decreased considerably. The
error is less than 0.05%: in the cases of Mars, Jupiter, and Neptune. The powers
3, 6, 9, and 12 for the moons of Jupiter give errors which average only one-third
as great as the original plan which did not include the mass term. Str.
An Alternative Explanation for the Red Shift
There has been much speculation during recent years as to the significance of
the “red shift” of the spectra of distant celestial bodies. It seems to be the pre-
vailing opinion that the red shift indicates that all distant bodies move away from
the earth, and that the speeds with which they move away are proportional to their
respective distances from the earth. This conclusion is, however, so preposterous
that its final acceptance should be withheld until careful consideration has been
given to all alternative explanations.
It appears that the red shift can be accounted for in a more reasonable manner
by assuming that each train of light waves during its journey through space will
undergo a slight expansion. Since recent experiments have shown that light
waves exhibit many of the properties of corpuscles, it would appears to be not
unreasonable to assume that one of those properties which are exhibited by waves
and corpuscles alike is the tendency to expand. A single train of light waves be-
ing always very short as compared with interstellar distances, it would require
only an extremely small difference of velocity between the waves at the front and
rear ends of the train to produce the observed red shift.
30x 1421, Washington, D. C. Cart F. Krarrr.
The Height of the Auroral Band of June 8, 1931
The method used by the writer to compute the real height of the aurora of
September 18, 1930 (PoruLtar Astronomy, February, 1931, p. 112) has been suc-
cessfully applied, again in collaboration with Mr. B. C. Darling of Lansing, Mich.,
in obtaining a height for the auroral band of June 8, 1931. The bright streak,
stretching across the sky at about 11:00 p.m. (E.S.T.), was doubtless noticed by
many, and the writer trusts that the following data will prove of interest.
Using the same diagram as in the former article, the present display yields
the following figures: B = 73° 1’, S = 78° 33’, and hence C = 5° 32’. Then again
using the law of sines, we have b= 307.5, whence we obtain the height
h = 301.38 miles.
The writer is aware of the fact that this figure, as well as the 196.414 miles
obtained for the September display, is abnormally high in comparison to the
heights which have been obtained in Norway and Canada with photographic
General Notes
429
means, but nevertheless considers that his results are about as accurate as can
be obtained visually.
Again, both Mr. Darling and the writer will be pleased to receive any addi-
tional information concerning either this display or the one for which the height
was computed last September. i :
CLINTON B. Forp.
904 Forest Avenue, Ann Arbor, Michigan.
Planetary Progression Once More
In rapid succession new laws of planetary progression are proposed. It
seems as if the perfect law must be found some day—if such a law really exists.
But it seems to be more deeply hidden than a formula fully explaining the differ-
ential rotation of the sun.
The power law published in PopuLar Astronomy, June-July, 1931, certainly
brings the percentage of error down to a nice minimum. But this fine result is
obtained by modifying slightly the principles of harmony. Mathematically, pro-
gression means continued proportion, that is, it demands a constant ratio incre-
ment. To conform strictly with a harmonious law, the value of n (in Mr.
Pruett’s formula k" seci) should have to be raised in constant ratio,
This Mr. Pruett has done in the case of the four large satellites of Jupiter,
and with excellent result. In the case of the planets, however, k is raised to
powers in a somewhat arbitrary way, and the power law should therefore not be
directly compared with the other laws shown on page 361, PopuLAkR Astronomy,
June-July, 1931.
Still the law is not very well suited to Saturn. Saturn seems to be too close
to the sun at present to fit well into a system of progression. But Saturn is ap-
proaching the sun and has been doing so for a long time. And a law of progres-
sion should be viewed rather from a cosmogonic angle than from the view of pres-
ent day conditions. The question is: How was the solar system formed? How,
why, and when did the planets come into being?
Without taking it too seriously, is no indication to be found of Saturn being
a stranger in the solar system? Is the ringed planet a freak of nature, or a pro-
duct of that which the biologists call mutation ?
Accepting the tidal theory, could it not be possible that the two suns in pass-
ing exchanged some stuff? If both Saturn and Jupiter are children of the same
sun and born at the same time, why should the density of Saturn be so much less
today than the density of the bigger body Jupiter?
— a £ Hans A. ERICKSEN.
Kreftings gt. 5, Hgnefoss, Norway.
Note on the Origin of Loess
Three explanations have been offered as to the origin of loess, namely that it
is a wind deposit, a water deposit, and a volcanic deposit. There is yet one other
possible explanation and that is that loess may be of meteoric origin. The reasons
for this latter hypothesis are as follows: (1) The disregard of contour lines in
the deposit of loess, particularly in Chinese loess (a study of which forms the
basis of this note), favors a meteoric origin even better than that of an aeolian
deposit. (2) The chemical composition of loess is about that of stony meteorites,
though the same may be said for volcanic material. (3) The absence of horizon-
tal lamination is a serious objection to the wind and water hypothesis while it
430 General Notes
favors one of meteoric origin. (4) The vertical stratification of loess has never
been satisfactorily accounted for. Water, as from a fine drizzle of rain, would
descend unevenly on coming in contact with newly fallen meteoric matter and
would soon develop favored lines of flow while the finest material would be
segregated along these lines of flow and ultimately crystallized as is found in the
hollow tubes in loess. It is, of course, these lines of flow that cause the vertical
stratification. (5) Loess was laid down during the last glacial epoch and one
of the causes that has been urged for explaining the Ice Age is that the solar
system passed through a region rich in meteoric matter. (6) The angularity of
loess grains with little or no evidence of rounded edges is inconsistent with the
wind and water hypotheses but if the meteors of that period exploded to even
smaller bits than they do at present we should obtain a material not unlike loess,
The objections against the meteoric hypothesis of the origin of loess are as
follows: (1) Most astronomers seem to favor an equal distribution of meteorites
over the surface of the earth while loess is, of course, unequally distributed. The
actual data, however, on meteorite finds and falls favor an unequal distribution of
meteoric matter on the earth. (2) Loess contains frequent grains of quartz and
mica scales while present meteorites very rarely do, but we need not assume that
meteoric material in the past has always been exactly the same as that now.
(3) At present meteoric matter reaches the earth either in the form of microscopic
dust from burnt-out meteors or else as bodies of considerable size varying froma
few grains in weight to several hundred pounds. Meteors do explode and the
disintegration in the past may have been more complete than that now, thus pro-
ducing the fine material of loess.
Although the origin of loess has never been satisfactorily explained, the possi-
bility of a meteoric origin seems to have been overlooked in the literature on the
subject. Further investigation is necessary before this new explanation can be
accepted but it does seem worth noting because of its bearing on the Lockyer
meteoric hypothesis and on the Chamberlin-Moulton planetesimal hypothesis.
a J. B. PENNISTON.
Cashmere, Washington.
Photographs of the Planet Mercury*
Photographs of the physical appearance of the planet Mercury are extremely
difficult to secure because this planet remains always close to the sun. Even at the
times of the greatest elongations (ranging from 18° to 28° from the sun) the
elevation of Mercury is quite small. The images are therefore always violently
agitated. The ideal way would be to make the photographs in full daylight when
the planet is near culmination. I intend to experiment in that direction, which
has its own difficulties but these ought not to be insuperable in view of the recent
developments in photographic technique.
On April 30, 1930, I succeeded in getting some photographs of Mercury at its
evening elongation but the images were so unsteady that no detail was recorded.
Recently on April 11, 1931, I found the images much better and therefore made
another attempt; the instrument used was a Viennet photographic lens mounted
on the refractor of the Flammarion Observatory at Juvisy. This lens has an aper-
ture of 0".160 (6% in.) and a focal length of 2”.90 (113 in.). The focal image
was enlarged nine times by means of a positive lens comprising two plano-convex
elements. On the date mentioned the diameter of Mercury was 779. The plates
*Translated from the French by G. Van Biesbroeck.
~~ — ae
-
se
General Notes
used had a speed of 700H and D. Four of them were exposed:
G.M.T. Images Exposures
h m
18 57 3 3 to 4sec
18 59 2 3 to 4 sec
19 8 3 2 to 3 sec
19 15 2 1 to3 sec
These ten images differ much in sharpness according to the momentary steadiness
of the atmosphere. Two exposures are satisfactory, four others are less so, and
the four remaining ones are of no value because they are either underexposed or
too indistinct. The best images were those on the first plate.
\ visual observation with the refractor of 0.24 aperture (914 in.) revealed
at once the presence on Mercury of a white region a little south of the center, not
far from the terminator, as well as a rather dark spot above the white spot. The
latter was bordered also on the north side by a darker region but it was not as
dark as the southern region. The clearness of these features is what induced me
to try photographing immediately. Six of the images unquestionably show the
details seen with the visual telescope. The central white region seems even to
invade the terminator, evidently through the effect of irradiation and the presence
of darker regions both to the north and the south. The images have been re-
copied and enlarged, after which they still show the details of the original plates.
But to reproduce them is very difficult on account of the small scale;t I there-
fore made the drawing reproduced herewith, showing the details that a close
study of the plates brought out. This drawing, it will be understood, is not the
reproduction of any particular plate but the result of the study of six plates taken
April 11, 1931.
S
DRAWING OF MERCURY FROM SIX PLATES TAKEN 1931 Aprit 11 BETWEEN
18"57™ anv 19"8™ U.T. sy F. QueENISSET.
I believe that this is the first time that any detail on the surface of Mercury
has been photographed. In 1911 and in 1921 I was the first to secure photographs
on the planet Venus. [See C.R., Paris, 153, p. 208 (1911) and 172, p. 1645 (1921),
or Bull. Soc. Astr. France, 27, 53 (1913) ; 36, 126 (1922) ].
The photographic plate appears often superior to the eye in registering small
differences in shadings existent on planetary surfaces. In the case of Mercury I
have just made a beginning, but I hope to do better in the future. In the mean-
time I thought it best to mention this result so that better equipped and better
located observatories would follow it up. :
F, QUENISSET.
*The author sent four enlarged prints of his plate but these are not suitable
for reproduction.
432 General Notes
The Dark Spots of Mare Crisium
These are the results of observations carried on in 1920-1922 with the help of
a telescope of 41 millimeters, magnifying power 94.
Several dark spots lie within Mare Crisium. When the sun is low the spots
are invisible. At that time the color of the Sea is a yellowish green. Before sun-
set Mare Crisium is gray.
Soon after sunrise there is a dark ring around the crater. When the longi-
tude of the morning terminator is +28° there is visible a triangular spot. Near
the first quarter this spot is bounded by two bright beams. The spot occurs when
the evening terminator is in longitude 60°.
Another spot is visible when the longitude of the morning terminator is +8°
and longitude of the evening terminator +60°. The size of the spot varies. To
the west of this spot there is a bright spot. The spot is of variable brightness.
These variations correspond to the variations of the bright spot Linné, but this
spot is fainter.
Two other spots are visible when the morning terminator is in longitude +-28°
and +8° and the evening terminator in longitude +75° and +71°, respectively.
A group of four spots is visible when the morning terminator is in longitude
+28° and the evening terminator in longitude from +75° to +465°.
I have also carried out some observations with red, dark blue, yellow, and
sreen filters. r
—— V. TSHERNOV.
Oktjabrskaja 77 Kremen¢ug, 2, Ukraine.
Stars and Interstellar Matter.
It is a well known fact among astronomers that there is no such thing as
empty space. In the first place it is filled with a thin cloud of sodium and ionized
calcium vapors, of a density of about one atom to the cubic centimeter, which is
responsible for the appearance of the D lines of sodium and the H and K lines
of calcium in the spectra of the hotter stars. In the case of larger particles it
would seem from observations that slightly over half of the meteors, and nearly all
of the fireballs have a hyperbolic velocity when they strike the earth, and are
therefore unattached to the solar system. Then, although there is no direct evi-
dence for the existence of any such bodies, it seems extremely probable that there
are bodies of planetary dimensions coursing through the depths of interstellar
space.
The purpose of this article is to describe the effects of this ever present but
very irregularly distributed cloud of matter upon the stars. I say irregularly dis-
tributed because in some places the merest traces are present,—while in other
places it forms those vast obscuring dark nebulae, whose presence in the heavens
was detected by Barnard.
The most important effect on the stars of this interstellar matter is that it
slows down or even reverses stellar evolution. This is how it comes about. Mass
and energy are interchangeable. The stars are enabled to shine only by radiating
away their mass, by a process which closely resembles, in some respects at least,
radioactivity: Therefore as a star becomes older, it becomes less massive. And
as the more massive stars are the brighter, the stars become fainter as they grow
older.
A very small percentage of a star’s mass will keep it shining for a very long
period indeed. At its present rate of radiation, the sun will have to shine for
about 15,000,000,000,000 years to shrink to half its present mass. Of course, faint
General Notes 433
stars deteriorate much more slowly than brighter ones; so much more slowly in-
deed, that no matter how massive a star was to begin with, it would take only
10,000,000,000 years for it to shrink to a mass twice that of the sun.
It now becomes apparent that if during a given period of its history a star
absorbs matter from interstellar space of a mass equal to the mass of the matter
lost though radiation, the evolution of the star will be checked for that period.
And if the star absorbs more matter than it loses through radiation, the star will
become brighter, and will ascend the main sequence if a dwarf, and if a giant, it
will become a super-giant.
3ut of two stars of equal luminosity, the redder of the two will pick up more
meteoric matter under the same circumstances. In fact, there is a definite formula
governing this.
The volume of the cylinder in space swept out by the star in its motion will
be proportional to the square of the radius. And it will capture all the meteors
within the cylinder. As the radius varies inversely as the square of temperature,
it is apparent that for stars of equal luminosity, the amount of interstellar matter
picked up varies inversely as the fourth power of temperature; other things being
equal.
This law increases to a great extent the chances of a red star becoming highly
luminous and later retaining its luminosity. This fact alone would explain why
red stars of high luminosity; long period variables, irregular variables like Betel-
geuse, etc., are so much more common in space than B-stars of high luminosity,
like Alcyone and S Doradus.
In fact if we estimate the average temperature of the B-stars at 16,000° and
the average temperatue of the M-type giant stars at 3000° K, it will be seen that
the M-stars will pick up about 650 times the amount of interstellar matter that
the B-stars will, in the same field.
To give a concrete example of how this law works out in favor of red stars
we will compare the number of long period variables with the number of B-stars
showing bright hydrogen lines in their spectra. We choose this comparison be-
cause these two classes of stars have about the same absolute magnitude, namely,
—3, and because the method of discovery used for the two classes is the same;
namely, noting the bright hydrogen lines on spectrum photographs. According
to Miss Cecilia H. Payne, “Stars of High Luminosity,”
1927 long period variables known and only 171 Be-stars. This is only one of
several similar cases.
pages 45 and 99, there are
i
We will now give another property of the process of increase in mass and
luminosity of stars through their picking up of interstellar matter. There is a
definite upper limit in luminosity for each different type of star in a meteoric field
of given density. The proof of this is as follows: The amount of matter picked
up by the star is proportional to the product of the square of its radius and the
density of interstellar matter in the part of space it is passing through. The
luminosity is proportional to the product of the square of the radius and the
fourth power of the temperature. Therefore, if the star were to increase in mass
and luminosity by the absorption of interstellar matter, with its diameter remain-
ing constant, there will ultimately come a time when its loss by radiation will
equal its gain by absorption; after this the luminosity of the star will remain
steady. This rule of the upper limit holds good for all cases, except those cases
where the star increases its diameter faster than it increases the square root of
its luminosity. But if a star did this indefinitely it would ultimately cease to be a
star. The long period variables are stars of low temperature and enormous diam-
434 General Notes
eter. An unpublished discussion by the author shows certain ones at least to be of
unusually high mass. (The resulting high luminosity, of radiometric magnitude
—7, and thereabouts, is disguised by the large heat index.) Can it be that the
long period variables are examples of stars that have increased their radii faster
than the square roots of their luminosities? The author thinks it probable.
Is it too much to say that all or nearly all high luminosity stars owe their
large mass and high luminosity to the absorption of matter from interstellar space?
This seems to the author a much better theory than that these stars are newer
creations than the rest of the stars. It seems to be preferable to the old-star-
Planetary nebula-white dwarf theory of Sir James Jeans, described in his book,
“The Universe Around Us.”
Another effect that the author wishes to take up is the action of interstellar
matter on double stars. If the interstellar matter be dense enough in the region
of a double star, it will act as a resisting medium, shortening the period, and
reducing the orbit, by an action very similar to that which causes the shortening
of the period of Encke’s comet. It will also act by increasing the mass and gravi-
tational pull of the two stars, which, as the angular momentum must remain con-
stant, will also result in the reduction of the orbit and shortening of the period.
If this process continues long enough, the stars will pass within Roche’s limit,
and the smaller star of the pair will either be broken up into a ring (like the rings
of Saturn) or will be absorbed by the larger star.
These processes can probably explain eclipsing variables like V Puppis, with
their high mass and short period. It is to be noticed that in eclipsing variables,
high luminosity and short period have a very strong tendency to go hand in hand.
This tendency can be best explained by the theory that high luminosity and short
period are due to the same set of causes, and the effect of the absorption of in-
terstellar matter on an eclipsing variable would be to increase the mass and lumin-
osity and shorten the period at the same time. .
Another part that interstellar matter may play is the creation of variable
stars. It is a theory which has gained wide acceptance among astronomers that
novae are caused by the collision of main sequence dwarf stars with masses of
solid matter of planetary dimensions. It seems reasonable to believe that a similar
collision in the cases of a super-giant star would produce different and less catas-
trophic effects. For one thing a super-giant is far less dense than a main sequence
dwarf. Therefore the colliding body would be stopped more gently and give up
its energy more slowly. The super-giant would find it easy to make the required
thermodynamic adjustment. Another thing of importance is the fact that in the
super-giant the heat resulting from the collision would spread through the star
more rapidly, instead of remaining in one spot to dissolve atoms and release more
energy. It therefore seems that the consequence of such collision in the case of a
super-giant would be a temporary increase in diameter. But when the energy
caused by the collision had spent itself, as it would in the course of a few days or
weeks, the star would attempt to return to normal.
A rather complex operation in the integral calculus shows that this attempt to
return to normal diameter will overshoot its mark, leaving the star smaller than
its diameter of natural stability ; and the whole process will end in the star pulsat-
ing about its normal diameter, with a period that is inversely proportional to the
square root of the mean density.
It is a well-known fact that the Cepheids are super-giant stars in luminosity,
showing the c-characteristic and the small proper motions which characterize
super-giant stars. Their periods vary inversely as the square roots of their mean
—- ene to vie
-— ee fe
General Notes 435
densities. It therefore seems probable that Cepheid variables are the result of
collisions between ordinary super-giant stars and stray bodies of planetary di-
mensions.
NoAu W. McLeop.
Christine, North Dakota.
A Review in Astronomy
Most persons feel that there are many questions which might be asked about
astronomy. The subject is so vast and, unless one |
e has approached the field in a
systematic and careful manner, the entire subject seems to be one great question.
Mr. F. D. Tubbs, 809 West California Ave., Urbana, Illinois, has submitted a list
of thought-provoking questions, the answers to which do not lie too deeply hidden.
Here are a few of them. Numbers 1 to 14 appeared in the preceding issue. Any-
one wishing to formulate answers to these questions is encouraged to do so. The
answers will be given careful consideration and corrected, if necessary, and re-
turned, if they are sent either to the editor or to the proposer mentioned above.
15. What seems to you the most distinctive fact about each of the planets?
16. What can you say of the contents of “empty” space:
17. What reasons have you for thinking that worlds are few? many?
18. If the planes of the orbits of the Earth and the Moon coincide, how often
would eclipses occur? What kinds of eclipses?
19. What can you say of windstorms on the Moon? On Jupiter?
20. Name five unsolved problems in astronomy.
21. How can it be proved by telephoning that the Earth is not flat but curved
from east to west? How prove the same from north to south?
22. How much radiant energy (in H.P.) does the Sun give off? What is the
radiant energy of the known universe, if the Sun is an average star, if there
are ten million stars in an average galaxy, and if there are two million
galaxies?
y
23. Why does the Earth continue moving?
24. On the average how far apart are moons? galaxies?
h that of the
; -
telescope wit
25. Compare the light-gathering power of a
average human eye.
26. Why would the constellations appear the same from all parts of the Solar
System?
27. Compare the phases of the Earth as seen from the Moon with those of the
Moon as viewed from the Earth.
28. In what month are noon-time shadows longest?
29. When and why does the Sun shine on both poles of the Earth at the same
time? Give more than one reason.
30. Why is the Moon nearer an observer when on his meridian than when in the
east or the west?
31. When a camera shutter has been open 1/100 sec. how many miles of light
have entered? How many “waves
32. Where now is the light that left the Sun 8 minutes ago? 8 hours? 8 years?
one million years? one hundred and fifty million years ago?
33. Describe the sky as viewed from Mars. From Jupiter. From the Moon.
34. What is the weight of the Earth? Of the Sun? Of the stars according to
the terms stated in question 22?
35. Since few stars have been measured how can stars as a class be said to re-
semble the Sun in size?
36. What results would follow if the Moon were annihilated? If Jupiter?
37. How many “points” has a star?!
436 Book Reviews
38. What is the apparent diameter of the Sun as seen from Jupiter? From Pluto?
From Alpha Centauri?
39. How often does morning come on Saturn? On the Moon?
40. What difference has the study of astronomy made in your thinking?
BOOK REVIEWS
Astronomy, by Forest Ray Moulton, Ph.D., Sc.D. (The Macmillan Company,
60 Fifth Avenue, New York City. Price $3.75.)
Although Dr. Moulton discontinued actual class-room lectures a few years
ago, he will ever be remembered as Professor Moulton by a large number of men
and women who had the rare privilege of coming under his influence and have
had the inspiration of his teaching. In a conversation in 1926, Professor Moulton
said that he was going to rewrite his textbook on descriptive astronomy. Since
then, the writer and, he feels safe in saying, many others who know the powers
of clear exposition possessed by Professor Moulton have eagerly awaited the
appearance of the new volume, which has recently been published.
This work gives in one volume of 533 pages a complete presentation of the
status of astronomical science at the present moment. The author devotes a
brief chapter at the beginning to preliminary considerations, designed to put the
reader in the proper attitude of mind to approach this the oldest and in some
respects the most basic of the sciences. In the second chapter he discusses the
most obvious of the material of this science, namely the visible starry sky. A
careful study of this chapter will give one an acquaintance and a familiarity with
the brightest stars individually and with the constellations which will be an un-
ending source of pleasure to him. To facilitate this an excellent list of charts is
given, showing the boundaries of the constellations according to the most recently
adopted system. Fifteen of the northern constellations are described in detail.
Chapter three, consisting of twenty-six pages, is given to an explanation of the
modern astronomer’s instrumental equipment and the methods of using it.
After this the development of the book proceeds according to the pedagogical
principle of passing from the known to the unknown. In this case this involves
starting with the facts concerning the earth, which are close at hand and in some
cases observable by anyone, and proceeding by easy, well-considered, and logical
steps to the more remote parts of the solar system, the stellar system, the system
of stellar systems, and finally to the super-galaxies and beyond.
A reading of this volume leaves one deeply impressed with the vast amount
of definite information now available. He is equally impressed with the many
questions as yet unanswered. With perfect candor, which is not always found
in scientific writing, the author closes many discussions with the thought that, al-
though observations and theory point in certain directions, it is not safe as yet to
draw definite and final conclusions.
One finds throughout the book the same qualities as were present in Professor
Moulton’s lectures, namely, a profound understanding of the subject and great
depth and comprehensiveness of thought. A set of circumstances, which to most
persons would constitute a closed, complete system, to the author, in the vast
sweep of his ideas, becomes a special case under a more general concept. He
does not discount a contribution however small, and he does not over-exalt one
however large. This is well illustrated in his comments on relativity (pp. 152-3).
_
we Sh =
we
—- (9
~~ i fe oe
‘v
Book Reviews 437
“This theory is no more absolute and final than other theories have been, and it
is probable that it is only a very important step in the evolution of science. ‘
Whatever its future may be, it marks a turning point in the mingled stream of
science and philosophy.” Professor Moulton’s capacity for keen analysis, his
maturity of thought, his accurate evaluations, and his fair mindedness, qualify
him for and entitle him to a place in the forefront among writers and workers in
science.
The book is replete with excellent illustrations, is beautifully bound, and is of
a convenient size. It is not only an admirable textbook for college classes in
astronomy but also a reference volume of modern, complete, and authentic in-
formation concerning present day astronomical knowledge and beliefs.
The Stars in Their Courses, by Sir James Jeans. (The Macmillan Company,
New York. $2.50.)
This is the most recent and also the most elementary book by this well-known
writer. The book consists of the material used in a series of radio talks expanded
to about twice its original length. As the talks were intended for those who had
no scientific training, this book is therefore well adapted to readers who wish to
begin at the beginning of the astronomical science. It is quite unusual that the
same writer should produce books varying s«
greatly in their depth of thought
as those of Sir James Jeans. This fact at once commends the present volume to
the average reader. He knows that the point of view he is getting is not that of
a novice but is that of one who is a leader among scientific investigators and
thinkers.
The traditional facts of elementary astronomy are given in a very clear and
interesting fashion. The book abounds in similes and comparisons which give the
reader a vivid picture of the ideas which are presented. For example, to convey
the idea that the spiral nebulae are very far away the author says, “If the first
man to inhabit the earth had built a wireless station and sent out ac calling
all stations in space to inquire if there were any other intelligent beings in the
universe, his call would not yet have reached the nearest of the nebulae.” When
he wishes to convey the impression of the great number of stars, he says, ‘
the total number of stars in the universe is probably about equal to the number of
drops of rain which fall on the whole of London in a day of heavy rain.”
Although the book begins with the elements of the science, in the 139 pages
the author leads one into the most modern and most profound ideas of the size,
age, and destiny of the universe.
There are twenty-seven supplementary pages designed to introduce one to the
visible sky. Thus one finds in one relatively small volume sufficient material to
make one who studies and comprehends it quite well educated in the basic science
of astronomy.
Man and the Stars or The Wider Aspects of Cosmogony, by Sir James H.
Jeans. (E. P. Dutton and Co. Inc., New York City. Price $1.00.)
This small sized volume of eighty-eight pages contains the Truman Wood
Lecture delivered before the Royal Society of Arts on March 7, 1928. It is not
only this lecture which is here printed but considerable additional material for
which the lecture did not afford time. The pages are so packed with new thoughts
and the material has to do with such recent and interesting developments in sci-
ence that one is at a loss, in a brief review like this, to know what part to mention
438 The Suns of Perseus
in particular. Perhaps the most striking impression left upon the reader is the
restricted horizon which until the last few years hemmed in men’s thinking. The
writer puts this idea into a sentence thus, “We cannot be too suspicious of the in-
terpretation which our minds, trammeled with long brooding over, and experience
limited to one tiny corner, put on the greater universe we are just beginning to
discover.”
Again in stressing the ephemeral nature of the human race, or indeed all
forms of life, as compared with the span of time required for a star or a nebula
to run its course, he says, “Utterly inexperienced beings, we are standing at the
first flush of the dawn of civilization. . . . In time the glory of the morning must
fade into the light of common day, and this in some far distant age will give place
to evening twilight presaging the final eternal night. But we children of the dawn
need give but little thought to the far-off sunset.”
The book is written in prose but is full of poetry. Anyone who reads this
small book understandingly will certainly have a new and enlarged view of the
universe.
Astronomischer Jahresbericht, compiled at the Astronomischen Rechen-
Institut, Berlin-Dahlem, and published by Walter de Gruyter and Co., Berlin and
Leipzig.
Volume 32 of this publication, containing the references to the literature
which appeared in 1930, has just been received. The references are classified un-
der ten general headings, each one having several sub-headings. The number of
publications to which references are given is 229, which shows the comprehensive-
ness of the index. Astronomers the world over have come to depend upon this
index as furnishing quick, accurate, and complete indication as to the location of
specific astronomical material.
THE SUNS OF PERSEUS
I gazed tonight upon the suns of Perseus
Blazing from the deep chasms of the night:
And thought how long, how long
These suns had rolled,
And shall roll in their orbits
Impotent forevermore,
While round them Time flows on
Itself lapping futilely at the shores of Eternity.
STERLING BUNCH.
Knoxville, Tennessee.
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